ClientQuotaManager threads prevent shutdown when encountering an error loading logs

While diagnosing KAFKA-6163, we noticed that when the broker initiates a shutdown sequence in response to an error loading the logs, the process never exits. The JVM appears to be waiting indefinitely for several non-deamon threads to terminate.

The threads in question are ThrottledRequestReaper-Request, ThrottledRequestReaper-Produce, and ThrottledRequestReaper-Fetch, so it appears we don't properly shutdown ClientQuotaManager in this situation.

QuotaManager shutdown is currently handled by KafkaApis, however KafkaApis will never be instantiated in the first place if we encounter an error loading the logs, so quotamangers are left dangling in that case.