Draft: One-off migrate apply group::container registry label

What does this MR do and why?

This applies the groupcontainer registry label to open Category:Container Registry and Category:Dependency Proxy issues, MRs, and epics.

The following is groupcontainer registry label assignment for below Category labels.

Category Label	Related Group Label
Category:Container Registry	groupcontainer registry
Category:Dependency Proxy	groupcontainer registry
Category:Package Registry	grouppackage registry
Category:Container Registry & Category:Dependency Proxy	groupcontainer registry
Category:Container Registry & Category:Package Registry	Keep the existing group label
Category:Dependency Proxy & Category:Package Registry	Keep the existing group label

Expected impact & dry-runs

Sample dry-run: https://gitlab.com/gitlab-org/quality/triage-ops/-/jobs/3258495068

• 613 + 88 issues will have groupcontainer registry
• 27 + 1 MRs will have groupcontainer registry
• 6 epics will have groupcontainer registry
• 18 issues with Category:Container Registry + Category:Dependency Proxy will have groupcontainer registry
• 739 issues will have grouppackage registry (Most of them have already labelled correctly)
• 45 epics will have grouppackage registry (Most of them have already labelled correctly)

Action items

• (If applicable) Add documentation to the handbook pages for Triage Operations =>
• (If applicable) Identify the affected groups and how to communicate to them:
  • /cc @person_or_group =>
  • Relevant Slack channels =>
  • Engineering week-in-review

Closes #1142 (closed)