Prereqs for pam_slurm_adopt

[tahliar]

From @e4t in #26:

@tahliar - I've read thru it and compared to the upstream documentation:
it seems like a lot of other prerequisites are to me met in order to make this work.
https://slurm.schedmd.com/pam_slurm_adopt.html
Either @mslacken or I will have to test this out again on a compute node and see what else is required to make this work. It seems this conflicts with systemd-logind, however, not running this may have further implications.