Update CI to be more streamline

[gerrod3]

No longer require fixes/noissue commit messages, added machinery to auto-label prs. Image testing CI will no longer run if only doc changes are present in a pr.

[patchback]

Backport to 3.49: 💔 cherry-picking failed — conflicts found

❌ Failed to cleanly apply c130256 on top of patchback/backports/3.49/c130256b4add3c49e20269b3795ba60f2680ecd6/pr-666

Backporting merged PR #666 into latest

1. Ensure you have a local repo clone of your fork. Unless you cloned it
   from the upstream, this would be your origin remote.
2. Make sure you have an upstream repo added as a remote too. In these
   instructions you'll refer to it by the name upstream. If you don't
   have it, here's how you can add it:

   $ git remote add upstream https://github.com/pulp/pulp-oci-images.git

3. Ensure you have the latest copy of upstream and prepare a branch
   that will hold the backported code:

   $ git fetch upstream
   $ git checkout -b patchback/backports/3.49/c130256b4add3c49e20269b3795ba60f2680ecd6/pr-666 upstream/3.49

4. Now, cherry-pick PR Update CI to be more streamline #666 contents into that branch:

   $ git cherry-pick -x c130256b4add3c49e20269b3795ba60f2680ecd6

   If it'll yell at you with something like fatal: Commit c130256b4add3c49e20269b3795ba60f2680ecd6 is a merge but no -m option was given., add -m 1 as follows instead:

   $ git cherry-pick -m1 -x c130256b4add3c49e20269b3795ba60f2680ecd6

5. At this point, you'll probably encounter some merge conflicts. You must
   resolve them in to preserve the patch from PR Update CI to be more streamline #666 as close to the
   original as possible.
6. Push this branch to your fork on GitHub:

   $ git push origin patchback/backports/3.49/c130256b4add3c49e20269b3795ba60f2680ecd6/pr-666

7. Create a PR, ensure that the CI is green. If it's not — update it so that
   the tests and any other checks pass. This is it!
   Now relax and wait for the maintainers to process your pull request
   when they have some cycles to do reviews. Don't worry — they'll tell you if
   any improvements are necessary when the time comes!

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