Alternate Addresses may not always be reachable

Related to K8S-3317 and other similar improvements to DNS lookups and reporting in the area of Alternate Addresses, it's worth bearing in mind that Alternate Addresses may not necessarily be reachable from within the Kubernetes cluster - these addresses could be ones used for NAT inbound to the cluster, in such a way that there may not be a route between the the Operator and/or Server Pods and the Alternate Address itself.

We should consider if blocking the publishing of Alternate Addresses until they are reachable is the right thing to do.