Resolve "StuckCiJobsWorker wrongly detects, cancels 'stuck' builds when per-job timeout is more than an hour"

What does this MR do?

Adds fine and coarse grained Ci::Runner#contacted_at management (with Redis).

Are there points in the code the reviewer needs to double check?

There are no specs for lib/api/helpers/runner.rb, which is why I haven't added specs for the changes I made to it.

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• N/A Documentation created/updated
• N/A API support added
• Tests added for this feature/bug
• Review
  • N/A Has been reviewed by UX
  • N/A Has been reviewed by Frontend
  • Has been reviewed by Backend
  • N/A Has been reviewed by Database
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together
• N/A Internationalization required/considered
• End-to-end tests pass (package-qa manual pipeline job)

What are the relevant issue numbers?

Closes #38265 (closed), #42196 (closed) and #42750 (closed)