Introduce network-based FQDNs via hiera

Introduce network-based FQDNs via hiera

Currently, one can get the network-based FQDNs via a custom puppet
fact. This is currently unreliable, as it's based on the ::hostname
fact which we assume it's set correctly by nova. However, this is not
necessarily the case (for instance, if you use pre-deployed services
such as we do with the multinode-jobs). In these cases, the
::hostname fact will return something other than what we specified in
nova, and effectively breaks the configurations in we relly too much
on the network-based FQDN facts.

By using hiera instead, we avoid this issue as we set those values to
be exactly what we expect (as we set them in the OS::TripleO::Server
resource.

Change-Id: I6ce31237098f57bdc0adfd3c42feef0073c224fb