[New Feature] Adjust the audio recording thread to High Priority

[mkckr0]

Describe the new feature you'd like
I propose to adjust the audio recording thread to high priority.

Describe the reason why you want to add the feature
I need this feature because it may reduce the latency.

Describe how to implement the feature if you can
Example: https://github.com/LizardByte/Sunshine/blob/nightly/src/audio.cpp

Additional context
#57

[airisama019]

I think I've reduced delay by lowering as-cmd nice value on htop
Feels almost instant now

[mkckr0]

https://github.com/LizardByte/Sunshine/blob/89e8b9628c9e4d763443fe871c45afe1fcf39396/src/platform/linux/misc.cpp#L284-L287

Sunshine doesn't implement adjust_thread_priority on Linux. Maybe there are some other things slow down the performance.