Prettier output

[simonLeary42]

This is all for slurm_gpustat:

• rearranged outputs: up, accessible, per-user, available -> up, accessible, available, per-user
• normalized the format of the outputs for count: gpu-name
• put the per-user section into a PrettyTable so that data is aligned
• sorted the available section because the other sections are sorted
• changed gpus to GPU's
• changed up to configured because it could mean down or drained
• changed accessible to up because it could mean unavailable
• made the divider an ALL_CAPS top-of-file variable
• made printing slurm_str optional
• made 'interactive' part of per-user optional

[simonLeary42]

I see slurm_gpustat is a separate repo, I will take my PR elsewhere