Allow selection of audio track

[scottAnselmo]

Describe the feature you'd like

Currently as far as I can tell, the audio track defaults to track 1 for Movies. There is no way to change this at will in the client from either the title meta card, or during mid-play. Only subtitles can be changed midplay. Easiest fix would probably be to update the subtitle selection popup to also have audio track selection.

Additional context

Reasons for implementing this are plentiful. For example, being able to listen to cast commentary tracks, or a non-track 1 language.

[boydthomson]

this would be great to be able to select original language or dubbed languages depending on who is watching and what they can understand