Simplify QA Issuer

Recently I noticed that we are still getting a lot of pings from QA issues for documentation, which shouldn't be the case. This was fixed in !560 (merged), and then updated recently to reflect the new documentation label in !937 (merged).

When I look at a recent QA issue, https://gitlab.com/gitlab-org/release/tasks/-/issues/1289, I still see a lot of "false positives", where documentation-only MRs are flagged as needing QA. Just by eyeballing it, it looks like it could even be close to 25%+ the MRs don't need to be in the QA issue as they are documentation changes only.

I think I finally figured out that this is because we are no longer relying on team labels, and instead we are working with the throughput labels to determine what kind of work is being done.

Proposal

Again, looking at the list in the last QA issue I was tagged on, it seems like we can:

• Use THROUGHPUT_LABELS (see throughput labels) to determine whether or not to add MRs to the QA issue, along with frontend, backend and database, to catch everything.
• Use TEAM_LABELS to sort the QA issue, and this should cover everything that needs to be added to the QA issue (except for Community contribution MRs, but that's a special case, since they can't label their own MRs). As a result, I think we can now also:
  • Remove all the deprecated labels, to make it easier to maintain.
  • Add devops::enablement, which was missing, and remove the groups that are listed under enablement.

Closes https://gitlab.com/gitlab-org/release-tools/-/issues/315