Slurm job submit plugin to submit jobs to different filesystem

Using slurm job submit plugin and node feature to submit the job to node with correct filesystem on nodes.

The slurm version on CoD is 19.05.5 which set the lua script dir to sysconfig at compile time, see slurm bug 11411. It's fixed later in version slurm-21-08-0-0rc1, which means the job_submit.lua has to be in /etc/slurm folder before that version.

Steps to enable lua interface for job submit plugin.

1. Add JobSubmitPlugins=lua line to Slurm.conf.
2. Place job_submit.lua file from the repo and place it in /etc/slurm or whereever your slurm.conf dir is present.
3. Execute scontrol reconfigure from Head node.