Feature Request: Add a configure subcommand to SwiftLint

New Issue Checklist

• Updated SwiftLint to the latest version
• I searched for existing GitHub issues

Describe the bug

The requested configure command is slightly akin to swift-format's dump-configuration command, or Periphery's --setup flag.

When run, configure will construct a .swiftlint.yml file. By default, configure would run interactively.

Additional command line options would allow configure to run non-interactively, accepting all the recommended defaults.

Additional command line options would allow configure's behaviour to be modifier still further - e.g., a threshold value, indicating that any rules with more then X violations should be disabled.

Additional command line options would allow configure to modify an existing configuration file.

A shell script follows in a comment which provides a proof-of-concept implementation of what configure might look like.

Additional features that could be added could be detection of files that should likely be excluded: files under Pods, or where generated or build appears in the path name, for example, and allowing the user to select a reporter.

Sample output when it's run at the top level of SwiftLint's source tree follows below:

% ./configure_swiftlint.sh
Welcome to the SwiftLint configuration assistant. Press any key to begin.
Checking for existing configuration files...
Found an existing configuration in .swiftlint.yml
Do you wish to continue? (Y/n) 
Found other configuration files:

./Tests/SwiftLintFrameworkTests/Resources/ProjectMock/NestedConfig/Test/.swiftlint.yml
./Tests/SwiftLintFrameworkTests/Resources/ProjectMock/NestedConfig/Test/Sub/.swiftlint.yml
./Tests/SwiftLintFrameworkTests/Resources/ProjectMock/ChildConfig/Cycle1/.swiftlint.yml
./Tests/SwiftLintFrameworkTests/Resources/ProjectMock/ChildConfig/Cycle2/.swiftlint.yml
./Tests/SwiftLintFrameworkTests/Resources/ProjectMock/ChildConfig/Cycle3/Main/.swiftlint.yml
./Tests/SwiftLintFrameworkTests/Resources/ProjectMock/ParentConfig/Cycle1/.swiftlint.yml
./Tests/SwiftLintFrameworkTests/Resources/ProjectMock/ParentConfig/Cycle2/.swiftlint.yml
./Tests/SwiftLintFrameworkTests/Resources/ProjectMock/ParentConfig/Cycle3/.swiftlint.yml
./Tests/SwiftLintFrameworkTests/Resources/ProjectMock/.swiftlint.yml
./Tests/SwiftLintFrameworkTests/Resources/ProjectMock/RemoteConfig/LocalRef/.swiftlint.yml
./Tests/SwiftLintFrameworkTests/Resources/ProjectMock/RemoteConfig/Cycle/.swiftlint.yml
./Tests/SwiftLintFrameworkTests/Resources/ProjectMock/Level1/Level2/.swiftlint.yml
./Tests/SwiftLintFrameworkTests/Resources/ProjectMock/Level1/Level2/Level3/.swiftlint.yml
./osscheck/builds/.swiftlint.yml
./osscheck/builds/Tests/SwiftLintFrameworkTests/Resources/ProjectMock/NestedConfig/Test/.swiftlint.yml
./osscheck/builds/Tests/SwiftLintFrameworkTests/Resources/ProjectMock/NestedConfig/Test/Sub/.swiftlint.yml
./osscheck/builds/Tests/SwiftLintFrameworkTests/Resources/ProjectMock/ChildConfig/Cycle1/.swiftlint.yml
./osscheck/builds/Tests/SwiftLintFrameworkTests/Resources/ProjectMock/ChildConfig/Cycle2/.swiftlint.yml
./osscheck/builds/Tests/SwiftLintFrameworkTests/Resources/ProjectMock/ChildConfig/Cycle3/Main/.swiftlint.yml
./osscheck/builds/Tests/SwiftLintFrameworkTests/Resources/ProjectMock/ParentConfig/Cycle1/.swiftlint.yml
./osscheck/builds/Tests/SwiftLintFrameworkTests/Resources/ProjectMock/ParentConfig/Cycle2/.swiftlint.yml
./osscheck/builds/Tests/SwiftLintFrameworkTests/Resources/ProjectMock/ParentConfig/Cycle3/.swiftlint.yml
./osscheck/builds/Tests/SwiftLintFrameworkTests/Resources/ProjectMock/.swiftlint.yml
./osscheck/builds/Tests/SwiftLintFrameworkTests/Resources/ProjectMock/RemoteConfig/LocalRef/.swiftlint.yml
./osscheck/builds/Tests/SwiftLintFrameworkTests/Resources/ProjectMock/RemoteConfig/Cycle/.swiftlint.yml
./osscheck/builds/Tests/SwiftLintFrameworkTests/Resources/ProjectMock/Level1/Level2/.swiftlint.yml
./osscheck/builds/Tests/SwiftLintFrameworkTests/Resources/ProjectMock/Level1/Level2/Level3/.swiftlint.yml

Do you wish to continue? (Y/n) 
Checking for swift files...
Found swift source files in the following directories:

Plugins
Source
Tests
osscheck

Do you wish to continue? (Y/n) 
Do you want SwiftLint to scan all the directories listed above? (Y/n) n
Do you want SwiftLint to scan source files in the "Plugins" directory? (Y/n) 
Do you want SwiftLint to scan source files in the "Source" directory? (Y/n) 
Do you want SwiftLint to scan source files in the "Tests" directory? (Y/n) 
Do you want SwiftLint to scan source files in the "osscheck" directory? (Y/n) n
configure_excluded
Checking for swift rules violations...
Found rule violations.
Do you want to disable all the rules with current violations? (Y/n) n
Do you want to the disable the "explicit_type_interface" rule (3,518 violations in 485 files)? (Y/n) 
Do you want to the disable the "explicit_acl" rule (3,376 violations in 505 files)? (Y/n) 
Do you want to the disable the "indentation_width" rule (1,625 violations in 316 files)? (Y/n) 
Do you want to the disable the "prefer_nimble" rule (788 violations in 58 files)? (Y/n) 
Do you want to the disable the "multiline_arguments_brackets" rule (749 violations in 128 files)? (Y/n) 
Do you want to the disable the "explicit_top_level_acl" rule (676 violations in 421 files)? (Y/n) 
Do you want to the disable the "type_contents_order" rule (657 violations in 270 files)? (Y/n) 
Do you want to the disable the "required_deinit" rule (558 violations in 281 files)? (Y/n) 
Do you want to the disable the "no_magic_numbers" rule (537 violations in 90 files)? (Y/n) 
Do you want to the disable the "implicit_return" rule (448 violations in 200 files)? (Y/n) 
Do you want to the disable the "no_extension_access_modifier" rule (386 violations in 212 files)? (Y/n) 
Do you want to the disable the "multiline_parameters_brackets" rule (250 violations in 68 files)? (Y/n) 
Do you want to the disable the "multiline_arguments" rule (223 violations in 58 files)? (Y/n) 
Do you want to the disable the "anonymous_argument_in_multiline_closure" rule (188 violations in 72 files)? (Y/n) 
Do you want to the disable the "file_types_order" rule (179 violations in 92 files)? (Y/n) 
Do you want to the disable the "no_grouping_extension" rule (166 violations in 153 files)? (Y/n) 
Do you want to the disable the "multiline_literal_brackets" rule (122 violations in 31 files)? (Y/n) 
Do you want to the disable the "force_unwrapping" rule (103 violations in 36 files)? (Y/n) 
Do you want to the disable the "vertical_whitespace_between_cases" rule (101 violations in 43 files)? (Y/n) 
Do you want to the disable the "conditional_returns_on_newline" rule (82 violations in 53 files)? (Y/n) 
Do you want to the disable the "trailing_closure" rule (80 violations in 47 files)? (Y/n) 
Do you want to the disable the "explicit_enum_raw_value" rule (78 violations in 14 files)? (Y/n) 
Do you want to the disable the "missing_docs" rule (70 violations in 13 files)? (Y/n) 
Do you want to the disable the "switch_case_on_newline" rule (63 violations in 12 files)? (Y/n) 
Do you want to the disable the "prefixed_toplevel_constant" rule (53 violations in 27 files)? (Y/n) 
Do you want to the disable the "convenience_type" rule (52 violations in 48 files)? (Y/n) 
Do you want to the disable the "strict_fileprivate" rule (52 violations in 21 files)? (Y/n) 
Do you want to the disable the "multiline_parameters" rule (51 violations in 32 files)? (Y/n) 
Do you want to the disable the "multiline_function_chains" rule (44 violations in 28 files)? (Y/n) 
Do you want to the disable the "discouraged_optional_collection" rule (25 violations in 15 files)? (Y/n) 
Do you want to the disable the "function_default_parameter_at_end" rule (18 violations in 12 files)? (Y/n) 
Do you want to the disable the "file_name" rule (17 violations in 17 files)? (Y/n) 
Do you want to the disable the "type_body_length" rule (17 violations in 17 files)? (Y/n) 
Do you want to the disable the "closure_body_length" rule (15 violations in 6 files)? (Y/n) 
Do you want to the disable the "function_body_length" rule (8 violations in 7 files)? (Y/n) 
Do you want to the disable the "large_tuple" rule (7 violations in 7 files)? (Y/n) 
Do you want to the disable the "number_separator" rule (7 violations in 5 files)? (Y/n) 
Do you want to the disable the "implicitly_unwrapped_optional" rule (6 violations in 5 files)? (Y/n) 
Do you want to the disable the "type_name" rule (6 violations in 6 files)? (Y/n) 
Do you want to the disable the "file_header" rule (5 violations in 5 files)? (Y/n) 
Do you want to the disable the "attributes" rule (4 violations in 4 files)? (Y/n) 
Do you want to the disable the "self_binding" rule (4 violations in 3 files)? (Y/n) 
Do you want to the disable the "superfluous_disable_command" rule (4 violations in 3 files)? (Y/n) 
Do you want to the disable the "empty_xctest_method" rule (1 violations in 1 files)? (Y/n) 
Do you want to the disable the "legacy_objc_type" rule (1 violations in 1 files)? (Y/n) 
Do you want to the disable the "prefer_self_in_static_references" rule (1 violations in 1 files)? (Y/n) 
configure_reporter
Printing configuration...

included:
  - Plugins
  - Source
  - Tests

opt_in_rules:
  - all

disabled_rules:
  - explicit_type_interface
  - explicit_acl
  - indentation_width
  - prefer_nimble
  - multiline_arguments_brackets
  - explicit_top_level_acl
  - type_contents_order
  - required_deinit
  - no_magic_numbers
  - implicit_return
  - no_extension_access_modifier
  - multiline_parameters_brackets
  - multiline_arguments
  - anonymous_argument_in_multiline_closure
  - file_types_order
  - no_grouping_extension
  - multiline_literal_brackets
  - force_unwrapping
  - vertical_whitespace_between_cases
  - conditional_returns_on_newline
  - trailing_closure
  - explicit_enum_raw_value
  - missing_docs
  - switch_case_on_newline
  - prefixed_toplevel_constant
  - convenience_type
  - strict_fileprivate
  - multiline_parameters
  - multiline_function_chains
  - discouraged_optional_collection
  - function_default_parameter_at_end
  - file_name
  - type_body_length
  - closure_body_length
  - function_body_length
  - large_tuple
  - number_separator
  - implicitly_unwrapped_optional
  - type_name
  - file_header
  - attributes
  - self_binding
  - superfluous_disable_command
  - empty_xctest_method
  - legacy_objc_type
  - prefer_self_in_static_references

Review the proposed configure command and the proof-of-concept shell script referenced in the issue, starting with SwiftLint's command-line entry point. Done requires agreeing on a bounded initial scope and implementing the command's configuration-file generation and documented interactive or non-interactive behavior.