For the multi-tenant KV layer, the admission control system gives equal weight to all active tenants.
However, different tenants may have different number of ranges at that node. For better fairness, we could introduce weighted fairness in the KV slot allocation, and weight by the number of replicas the tenant has on that node.

Note that the slot allocation doesn't consider actual resource consumption -- if one tenant has queries with higher contention, it will consume more slots, even though it is not actually consuming resources.

Jira issue: CRDB-13549