Need an improved health check

[cehbrecht]

Description

The current health endpoint used by the load-balancer only checks the getcapabilities request. But it should also check if jobs can still be submitted (issues with slurm queue, filesystem down, ...).

Maybe add a health process which runs quickly but gives us the possibility to add the checks we want?

Environment

• rook version used, if any: 0.4.1
• Python version, if any:
• Operating System:

Steps to Reproduce

Additional Information