Add a new function like GetHostName that returns the internal name of the service

[smuu]

Currently, only GetIP is available to connect to other instances. This IP is from the service and not from the Pod, so it adds problems to p2p connections. As Pod IPs are ephemeral we cannot return it, as it might change.

The idea is to use a headless service that translates the service's name to the pod's IP. The developer can then use this host name to connect to other instances.

Related: #514