acousticbrainz-git: created

This still uses the pre-made essentia binary provided by acousticbrainz.
essentia-acousticbrainz: created from essentia

This uses a specific commit that is also used for the
acousticbrainz-provided binaries.
We build that one example the acousticbrainz-client needs
and only install that. No conflict with the essentia package.
acousticbrainz-client-git: use essentia-acousticbrainz

We don't use binaries anymore now.
essentia-acousticbrainz: minor cleanup