User creation/deletion latency keeps increasing due to tombstones

As seen in CBSE-10742, customer need to create/delete large number of users in short succession. The customer is using secrete management solution (such as HashiCorp) in Kubernetes, where containers are created and destroyed in quick succession, and for each container, an ephemeral user is created and destroyed as well.

Current user CRUD API latency increases as number of users increases, due to the implementation nature of replication (replicated_dets).