RFC: Realtime system (audio) group

[Adrian Knoth <adi@drcomp.erfurt.thur.de>]

Hi!

[background story: pro-audio applications run with POSIX realtime
priorities to meet low-latency deadlines. We ship
/etc/security/limits.d/audio.conf in the jackd packages to grant rt
privileges to the audio group]

As outlined in #656910, "being in the audio group" and "having realtime
priorities" aren't separated at the moment.

To make these two independent, we'd need to use a different (new?) group
for realtime priorities.

We can call this group "rtaudio", but maybe somebody prefers a more
generic name, e.g., "realtime". Maybe there is already such a group.


WDYT?


Cheers