Need to be able to add new database in pg_hba.conf

SO, for gluster, we found that we also need to edit pg_hba.conf to add access to a remote database. ( https://bugzilla.redhat.com/show_bug.cgi?id=1393292 )

So far, i did a fork to hardcode that so Nigel can work on the rest, but I would like to see how we can do that cleanly.

As I would propose to make sure we enforce best practices and proper integration, I am not sure if we want to directly expose the ACL, or if we want something that would create database and users, or enforce a specific naming scheme (like user==db everytime, etc)

This is also tied on the ssl part, as I think we should enforce ssl for network connection.