Move libvert concerns into it's own role

[billwheatley]

Since libvirt is more than a single package, having also containing adding the user to the libvirt supplemental group. In addition there are other related packages as well that go along with this as well.

Since a number of these are dependent and related they should be refactored to a role so the concerns can be bundled together instead of sprinkled thought the playbooks.

NOTE: chances are there maybe a role on Ansible galaxy for this already and should be explored.