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)