Enhance an event mechanism to notify client about a redis cluster TopologyRefresh.

[kimmking]

Expected behavior

Notice lettuce could fire an AdaptiveRefreshScheduledEvent event to subcribe it by client api when Redis Cluster TopologyRefresh. And then client codes can do something for HA/consistency functions. So I think we can add an similar event with renewSlotCache to refresh cluster view in method redis.clients.jedis.executors.ClusterCommandExecutor#executeCommand.

Actual behavior

Add a new event mechanism.

Steps to reproduce:

NONE.