add role ssh-keepalive, which uses  keepalive packets to prevent firewalls closing inactive ssh connections

depending upon node. This is done by a script nvidia-probe.py which probes node for correct information

add role enable_modules (and remove enable_lmod) use enable_modules to select either lmod or modulecmd being source from /etc/profile.d on Login and Compute nodes

allow provision_slurm to take a path to the lockfile so its on a directory shared between managment nodes