API docs for the whole stack via doxygen (backport #278)

[mergify]

Instead of running doxygen only on ros2_control repo, I implemented it now for all repositories at once.

This made some changes necessary to the helper scripts: I converted them to python scripts, because it would have been to complicated to formulate the repository-maps with bash scripts.

The doxyfile is moved over from ros2_control, but with updating it to a new doxygen version.

main page

example controller page

---

This is an automatic backport of pull request #278 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of 56c9fcb has failed:

On branch mergify/bp/iron/pr-278
Your branch is up to date with 'origin/iron'.

You are currently cherry-picking commit 56c9fcb.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   .github/workflows/ci-format.yml
	modified:   .gitignore
	modified:   Makefile
	modified:   doc/api_list/api_list.rst
	modified:   doc/api_list/mainpage.md
	modified:   index.rst
	deleted:    make_help_scripts/add_pr_stats
	new file:   make_help_scripts/add_pr_stats.py
	deleted:    make_help_scripts/add_sub_repos
	new file:   make_help_scripts/add_sub_repos.py
	deleted:    make_help_scripts/add_tmp_commits
	new file:   make_help_scripts/add_tmp_commits.py
	deleted:    make_help_scripts/check_links
	new file:   make_help_scripts/check_links.py
	deleted:    make_help_scripts/create_api
	new file:   make_help_scripts/create_api.py
	deleted:    make_help_scripts/create_api_multi_version
	new file:   make_help_scripts/create_api_multi_version.py
	modified:   make_help_scripts/create_pr_stats.py
	deleted:    make_help_scripts/delete_sub_repos
	new file:   make_help_scripts/delete_sub_repos.py
	deleted:    make_help_scripts/delete_tmp_commits
	new file:   make_help_scripts/delete_tmp_commits.py
	new file:   make_help_scripts/deploy_defines.py

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	deleted by us:   .github/workflows/sphinx-check-page-multiversion.yml
	both modified:   conf.py
	deleted by them: make_help_scripts/deploy_defines

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally