Change sample rate option

[Bleuzen]

I would like to be able to set LMMS sample rate to 48kHz, but I can't find an option for this. The only way I found is to use Jack as backend and let Jack run at 48kHz, but without Jack, LMMS always forces 44.1kHz. I already set my PulseAudio default sample rate to 48kHz, but LMMS still plays at 44.1kHz with all backends excepting Jack. A drop down menu in settings where we can set the sample rate would be nice.

The reason for this? Well, all my hardware is natively 48kkHz, so I could avoid resampling where it is possible. Another reason is I always export at 48kHz. And as you can see in bugs like this: https://github.com/LMMS/lmms/issues/4606 it seems more stable if LMMS working and exporting samplerate are the same.

So please let us users decide which samplerate to use instead of forcing 44.1kHz.