Add sounds & music

[ozkriff]

I think that hey can be integrated into scene/actions system

[ozkriff]

The most basic stuff seems to work now: https://twitter.com/ozkriff/status/1303736184045174785

[ozkriff]

This should be enough for the first iteration:

zemeroth_sounds_demo-2020-12-21__18_30.aac.mp4

[ozkriff]

Going to make the quick final tweaks and prepare a PR in a couple of days (so that @not-fl3 could work on sounds on Android).