[Feature Request] Generic output formatting with global format parameter

Idea

Implement the output generating code in a way to have one or multiple parameters to specify the output formatting as a whole.

For example, some monitoring systems still use a single line as output, one might want to have output fitting on a pager or, and this is speculation for the future, properly machine readable output might be a thing.

Ideally, in the end I can do something like this:

# my_check --foo bar
[OK] all ok
  \_ [OK] bar

# my_check --foo bar --output one-line
[OK] all ok - [OK] bar


# my_check --foo bar --output whatever
ok - all ok : ok - bar

Start by locating the code that generates monitoring-plugin output and determine how command-line parameters are parsed. Compare the current multiline example with the proposed one-line and custom formats; done means a global output-format parameter supports a defined set of formats with clear behavior.