feat: Decouple creating bucket metrics from instrumenting the bucket

[kavirajk]

• [x] I added CHANGELOG entry for this change.
• [x] Change is not relevant to the end user.

Changes

Currently if a single process uses multiple object client, we get metrics duplicate registration failures.

With this PR,

1. New BucketMetrics API return just a Metrics that can be created once and used for multiple clients.
2. New Wrap API that takes metrics and returns instrumented bucket just like WrapWithMetrics API.

This PR doesn't change any existing API WrapWithMetrics

Verification

Not breaking any existing API(s). All existing tests passes