* Pressing shuffle will now show a notification indicating it is not
implemented.
* On the initial setup, the discovered settings are displayed somewhat
more neatly.
* Disable reloading the main view each time the MainPage gets activated.
- PlaybackManager now takes ownership of set items
- PlaybackManager can play items just by their itemId, avoids useless
item creation on the QML side of things.
- Allow calling Jellyfin::registerTypes with a different URI
- Minor code cleanup