[server] Added a throttler for AAWC workload of leader replica

[gaojieliu]

Summary, imperative, start upper case, don't end with a period

We know AA/WC workload is expensive and in the past, we were trying to limit the consumer pool for AA/WC leader to control the resource usage, but sometimes, it is not very accurate. This code change introduces a new throttler for Leader AA/WC workload, and it will only take effect when the dedicated consumer pool for AA/WC leader feature is enabled. New config: server.aa.wc.leader.quota.records.per.second : default (-1)

How was this PR tested?

CI

Does this PR introduce any user-facing changes?

• [X] No. You can skip the rest of this section.
• [ ] Yes. Make sure to explain your proposed changes and call out the behavior change.