* implement search for shows/podcasts
* create Playable supertype for queue to contain tracks and episodes
* wip: implement playback of episodes
* load spotify id from uri instead of raw id to fix podcast playback
* show duration for podcast episodes
* implement generic status bar for playables (tracks and episodes)
omit saved indicator for now as the library does not yet support podcasts
* instead of only the last 50 fetch all episodes of a show
* refactor: extract Playable code to separate file
* implement playback/queuing of shows + sharing url
* implement podcast library
* migrate mpris code to Playable supertype
