Avoid duplicate info about Hostname and Port in ClusterMapConfig and NetworkConfig

[jsjtzyy]

The hostname and port are currently recorded in ClusterMapConfig and NetworkConfig. We are supposed to avoid the duplicate information in two places for safety concerns. Maybe we can remove the hostname and port from NetworkConfig in the future.

[pnarayanan]

hostname is in fact triplicated in RouterConfig. I think ClusterMapConfig is the right place and all components wanting host and port should be able to source it from there.