Allow fetch of track description in tracks endpoint
As part of !1309 (merged), I'd like to expose episode descriptions in the
/api/v1/tracks/ endpoint so that a short description of podcast can be rendered inline and a modal created for easy access to show notes. Currently, episode descriptions can only be fetched by the
Since episode descriptions can be quite large, ideally this should be an optional parameter as podcasts and music both use this endpoint. I would only want to fetch this data for podcast episodes.