ClusterHealth returns view members, not servers in ready state

The `health.ClusterHealth.Nodes` returned by `/v2/cache-managers/

/health"` returns the members of the current JGroups view. This does not take into account whether those members are able to handle client requests via HotRod or REST. Currently the operator uses these values to determine whether a cluster is well-formed. Consequently there is a small window, when the number of replicas > 1, where requests to the most recently joined node will fail as the server has not finished startup.