Controllers: allow separating public & private services

This patch allows one to specify two networks (one for public and one for internal).
Services are monitored on both, and a vip exists for both.

Close #321
Separate resources reachability based on public/internal network.

Separate the resources so they can be instantiated in different
servers. It is a temporary fix that is backward compatible.
A bigger fix is n the way for the next version.

Close #321