Post-update testing

[jameshcorbett]

Brian asked to have a script that admins could run to give some reasonable assurance that the flux-dws integration works properly after a kubernetes and/or flux update on a rabbit cluster. We thought maybe it would make sense to have the script live in this repo and be deployed with the flux-coral2 RPM.

I was thinking it could just be a script that creates XFS/Lustre/GFS2 rabbit file systems with various capacities and names and check that the file systems are mounted properly, and then try creating and destroying persistent file systems.