Fix configuration retrieval service (PublicConfig) in Console

[ammendonca]

Currently console has a service defined for retrieving configuration called PublicConfig

https://github.com/RestComm/Restcomm-Connect/blob/master/restcomm/restcomm.ui/src/main/webapp/resources/js/services.js#L769-L779

But this service is not being properly initialized/used (eg, for retrieving rvdUrl), basically because it's not readily available at load time. This should be fixed and used where fit.

This is a blocker for #2897