Add fair call queue support to event processing queue.

HADOOP-15016 has support the fair call queue.

In HDFS-14403, hdfs support fair queue client RPC based user, i think the fair call also can be used to YARN event queue:

When event boom, the fair can let other normal event go, which can improvement the event boom's affection to yarn scheduler performance.

cc epayne jhung  wangda ztang bibinchundatt hcarrot  gandras

bteke ebadger

If you have any advice for this proposal.