gh-90300: split --help output into separate options (GH-30331)

Make --help output shorter and add new help options.

--help-env, --help-xoptions and --help-all command-line options are
added to complement --help.
(cherry picked from commit 8aa9d40b00741213c5a53b1ae15509998893ae31)

Co-authored-by: Éric <earaujo@caravan.coop>