New context with albums and lyrics +++ much more

* Added new lyrics provider with lyrics from AudD and API Seeds
* New improved context widget with albums and lyrics
* Fixed playing and context widget getting stuck in play mode when there was an error
* Changed icons for artists in collection, tidal and cover manager
* Removed "search" icon from "Search automatically" checkbox (right click) that looked ugly
* Removed some unused widgets from the src/widgets directory
* Fixed initial size of window and side panel
* Fixed saving window size correctly

src/core/player.h

@@ -95,10 +95,11 @@ class PlayerInterface : public QObject {
   virtual void Play() = 0;
   virtual void ShowOSD() = 0;
 
-signals:
+ signals:
   void Playing();
   void Paused();
   void Stopped();
+  void Error();
   void PlaylistFinished();
   void VolumeChanged(int volume);
   void Error(const QString &message);