[rbp] Remove PiAudio engine
[rbp] Add PiAudio sink
[rbp] Allow paplayer to be enabled on Pi
[rbp/omxplayer] Suspend AE when playing audio
[rbp/omxplayer] Remove visualisation support

This is now handled by paplayer
Revert "[rbp/omxplayer] Ignore video stream in audio filetypes"

This reverts commit ca5119d8bd73a632e6006e77cba7f59a37c3dbb2.