Add metrics for Historical cloning

[adarshsanjeev]

Add metrics for monitoring cloning and broker config syncing. These metrics are:

• config/brokerSync/time
• config/brokerSync/total/time
• config/brokerSync/error

Also addresses followup comments from #17899 including:

• Fixing documentation of context parameter
• Add a more graceful shutdown
• Rename some fields for consistency

---

This PR has:

• been self-reviewed.
  • using the concurrency checklist (Remove this item if the PR doesn't have any relation to concurrency.)
• added documentation for new or modified features or behaviors.
• a release note entry in the PR description.
• added Javadocs for most classes and all non-trivial methods. Linked related entities via Javadoc links.
• added or updated version, license, or notice information in licenses.yaml
• added comments explaining the "why" and the intent of the code wherever would not be obvious for an unfamiliar reader.
• added unit tests or modified existing tests to cover new code paths, ensuring the threshold for code coverage is met.
• added integration tests.
• been tested in a test Druid cluster.

[kfaraz]

Looks good, left some suggestions.