Instrument Geo::RepositorySyncWorker

What does this MR do?

Adds instrumentation to all Geo::RepositorySyncWorker instance methods

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

Why was this MR needed?

We need to investigate the performance characteristics of this class on the Geo testbed

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• API support added
• Tests added for this feature/bug
• Review
  • Has been reviewed by UX
  • Has been reviewed by Frontend
  • Has been reviewed by Backend
  • Has been reviewed by Database
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together

What are the relevant issue numbers?

Related to https://gitlab.com/gitlab-com/infrastructure/issues/2775 Related to https://gitlab.com/gitlab-org/gitlab-ee/issues/3453