Change to use asyncio rather than threading

[whi-tw]

This allows event-driven things to be far more easily driven (ie. pulsectl)

Also, Rather than defining a source / sync for the mute buttons, use the current default one - how often do you need to immediately mute a device that's not in use?

Also, bump python version to 3.10.0 to enable sweet sweet match case statements

[liljenstolpe]

I think both of these changes make sense. I was also thinking of using asyncio for the keylight deck so the buttons can show current state.