Add tests to check this feature
Apply config validation in config for simplicity
Note: if anything messes with the niceness (ie. it starts non-zero, or it's not the expected value during setup, we'll bail out)
SCHED_ISO is not supported by upstream kernels, so don't try to use this by
default since for most users it will result in an error log that trying to
set the scheduling policy fails.
Without extra system configuration, we will also not have permission to renice
processes by default, so out of the box doing this will fail as well.
Users that wish to use these features can enable them from the config once
they have configured their system appropriately.
