Update README.md to be consistent within ros-controls (backport #2154)

[mergify]

and

• remove CONTRIBUTING.mg (is automatically included from www.github.com/ros-controls/.github)
• remove workflows/readme, as we always forget to update it anyways
• remove issue/PR templates (will be automatically included from www.github.com/ros-controls/.github)

  ---

  This is an automatic backport of pull request Update README.md to be consistent within ros-controls #2154 done by Mergify.

[mergify]

Cherry-pick of c19997a has failed:

On branch mergify/bp/humble/pr-2154
Your branch is up to date with 'origin/humble'.

You are currently cherry-picking commit c19997a.
  (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:
	deleted:    .github/ISSUE_TEMPLATE/bug_report.md
	deleted:    .github/ISSUE_TEMPLATE/feature_request.md
	modified:   .github/workflows/README.md
	deleted:    CONTRIBUTING.md
	modified:   README.md

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	deleted by them: .github/ISSUE_TEMPLATE/good-first-issue.md
	deleted by them: .github/PULL_REQUEST_TEMPLATE/pull_request_template.md

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