Add basic youtube upload support

Add basic youtube upload support

Rather than using the Kodi youtube extension, this downloads the video
and extracts the audio has vorbis in order to apply
replaygain. Otherwise videos can be jarringly louder than music that's
properly replaygained.

This also has the benefit of working on the upstream Kodi and not just
my patched version that allows queuing videos when in party mode
without quitting party mode instantly.

No error checking whatsoever, and no attempt is made to display good
metadata in the queue yet.