?????? suport dynamic enable/disable health check #2947

[lordcheng10]

I don??t know if I have described it clearly, for example:
Here is a bookkeeper cluster with 3 nodes (b1, b2, b3), and the corresponding 
pulsar broker has 3 nodes (B1, B2, B3). When we restart the b1 and b2 nodes, 
the pulsar broker will switch b1, b2 Put it in the excludeBookies collection 
and isolate it for 30 minutes. At this time, when the pulsar broker chooses the 
bookie node, it can only choose the b3 node, so the traffic of the entire 
cluster will go to the b3 node at this time.