WIP: "Project dashboard appears to be loading tags on every request"

What does this MR do?

Better cache invalidation of git data, and start cache populate sooner after invalidations

What are the relevant issue numbers?

Closes #18709 (closed) or at least reduce the impact

Does this MR meet the acceptance criteria?

• CHANGELOG entry added
• [ ] Documentation created/updated
• [ ] API support added
• Tests
  • Added for this feature/bug
  • All builds are passing
• Conform by the style guides
• Branch has no merge conflicts with master (if you do - rebase it please)
• Squashed related commits together