Suggestion: add CPU and GPU level controls

Since ALVR is very lightweight on the headset side of things as it just does video decoding, it would make sense to turn down the GPU and CPU power levels to save power.

https://developers.meta.com/horizon/documentation/unity/os-cpu-gpu-levels/

From my testing with QGO and observing the performance and usage of the device resources, ALVR is perfectly capable of streaming native resolution at 120Hz on the Quest 2 with both CPU and GPU set to power level 0. By default ALVR uses the CPU and GPU both at power level 2.

I propose to either set the default mode of ALVR client to PowerSave for both GPU and CPU, or add a slider to the Dashboard to let the users switch power mode and level to fit their needs.

This would help reduce power consumption of the headset which is important to extend play time for people that are playing untethered, and would help reduce the ammount of wattage required to be provided by the USB port when using the device tethered.

Many USB-A ports on laptops and other devices don't provide enough power to actively charge the device while playing. Some are just regular 1A ports that provide the device with 5W. This results in the headset battery slowly draining despite being plugged in. Lower power consumption on the headset side would extend these cases of tethered play time too.

If you'd like, I can make an attempt to implement a feature like this myself.

I hope this makes sense, thank you!