This reverts merge request !167

changes to the config_repos role so hopefully we can upgrade cleanly without reinserting the base repos

M3 has decided to change where we store some parts of slurm, in particular prolog and epilog will go into /opt/slurm/etc

Refer to https://github.com/mej/nhc

Make slurmctld and slurmdbd explicitily disabled on startup (rather than just leaving it to whatever it is currently set to)

- template the public interface so NAT Masquerade command goes to right interface
- public inteface name autogenerated by looking at route to 8.8.8.8
- ACCEPT command for private interface modified to use network CIDR. THis is hardcoded to M3 if not defined, so no impact on cluster_in_a_box roles. (Monarch and others will need to pass it as a parameter)
- Not sure if ACCEPT on private interface is used, as compute nodes point to mlx0 interface for routing