Add group and stage label inference to GitLab Charts

The Helm Charts are stored within the GitLab charts group and not on gitlab-org. This means label inference is not run on the charts projects.

Applying the labels will enable issue and merge requests reporting by group/stage for the Charts projects. This would cause some chatter on issues & merge requests from GitLab Bot.

Charts are getting moved into gitlab-org eventually: gitlab-org/distribution/team-tasks#422 (closed)

Dry Run Results

Pipeline runs (as of 8/5):

• stage-and-group-labels-hygiene.yml - 69 matching issues: https://gitlab.com/gitlab-org/quality/triage-ops/-/jobs/266437366
• mr-migrate-legacy-labels.yml - 15 open merge requests & 294 merged merge requests: https://gitlab.com/gitlab-org/quality/triage-ops/-/jobs/266438245

Looking for feedback from @gitlab-org/distribution