Support advertised host to differentiate the address used for internal cluster communication from the externally exposed bootstrap server address

[swuferhong]

In many cases, coordinator.host and tabletServer.host can only be accessed internally within the cluster and cannot be used as the bootstrap server address for external connections to the Fluss cluster.
Currently, we do not have a mechanism in place to expose addresses that can access the cluster externally. Therefore, there is a need to introduce an advertised host to separate it from the internal communication addresses of the cluster.