[BADGER-226] Remove YouTube integration (for now, possibly for ever)

[markspolakovs]

It never left beta. Various bits of it have tendrils throughout the codebase (eg BADGER-167 has made the media and metadata code considerably more complicated), while a lot of it is just effectively dead code that makes refactoring annoying (e.g. the code to convert shows/rundowns to their YT equivalents would need considerable reworking for tree-ification).

_{From SyncLinear.com | BADGER-226}