Summary:
This revision adds two metrics:
- object_locking_lock_acquires - the total number of object lock acquires (from both Lock() calls
  and fastpath lock requests consumed).
- object_locking_fastpath_acquires - the total number of fastpath object lock acquires consumed.
Jira: DB-16853

Test Plan: Jenkins. Verified metrics on local cluster with enable_object_lock_fastpath on/off.

Reviewers: bkolagani

Reviewed By: bkolagani

Subscribers: ybase

Differential Revision: https://phorge.dev.yugabyte.com/D45525