packaging: refactored firewalld support

Added one service configuration template file for each service
that should be allowed by firewalld under
/usr/share/ovirt-engine/firewalld/*.

During firewalld configuration the template files will be processed
by processTemplate with provided ports.
Then the service files will be copied to /etc/firewalld/services
and enabled for the active zones.

The ovirt-aio service will be enabled only if the plugin is installed and
enabled.

Change-Id: If6a60e1667182f926f399e22bbfbb939e7171cb0
Signed-off-by: Sandro Bonazzola <sbonazzo@redhat.com>