FOSS build on Izzy's Repo

@IzzySoft v3 is a complete app rewrite and there is now a "FOSS" build-variant available (like in my other projects). Should we include that in your repo instead of the Google build? Currently only as "beta" build, but in a few weeks if nothing comes up, I'll promote an RC. https://github.com/d4rken-org/bluemusic/releases/tag/v3.0.0-beta0