Group arguments in the help text

Consider grouping related parameters and using this to help order them logically for users. For example, presently the --add-feature and --remove-feature appear in different locations spread through the options.

Metadata

Add an optional group key to variable definitions in metadata.obsah.yaml:

variables:
  foreman_initial_admin_username:
    help: Initial username for the admin user.
    group: Initialization
  foreman_initial_admin_password:
    help: Initial password for the admin user.
    group: Initialization
  certificates_cnames:
    help: Additional DNS name to include in Subject Alternative Names for certificates.
    action: append_unique
    type: FQDN
    parameter: --certificate-cname
    group: Certificates

Variables without a group are added to the default "options" section as they are today.

Group assignment via include

Included metadata files can define groups on their own variables. For example, _database_connection/metadata.obsah.yaml could set group: Database on all its variables, and when included by deploy, those arguments would appear grouped under "Database" in the help output.

Alternatively, the including file could specify a default group for all variables pulled from an include:

include:
  - name: _database_connection
    group: Database
  - name: _tuning
  - name: _flavor_features

This would assign the group to all variables from the included file that don't already have an explicit group set. The simple string form (- _database_connection) would continue to work as today with no group assignment.

Ordering

argparse displays argument groups in the order they are created. To control group ordering, a top-level groups key could define the display order:

groups:
  - Initialization
  - Certificates
  - Database
  - Tuning

variables:
  ...

Groups not listed in this ordering would appear after the listed groups. This key is optional — without it, groups appear in the order they are first encountered while iterating variables.

Proposed grouping for deploy

Start with deploy and its metadata.obsah.yaml, then inspect how included files such as _database_connection/metadata.obsah.yaml contribute variables to the help output. Implement optional variable and include groups plus top-level group ordering, preserving ungrouped options and the simple include form. Done means grouped arguments appear in the requested order and existing metadata without groups continues to work.