Refactor and temporarily disable sharing artists

backend/mediaprovider/mediaprovider.go

@@ -151,6 +151,7 @@ type SupportsRating interface {
 
 type SupportsSharing interface {
 	CreateShareURL(id string) (*url.URL, error)
+	CanShareArtists() bool
 }
 
 type JukeboxProvider interface {

backend/mediaprovider/subsonic/subsonicmediaprovider.go

@@ -330,6 +330,12 @@ func (s *subsonicMediaProvider) CreateShareURL(id string) (*url.URL, error) {
 	return shareUrl, nil
 }
 
+func (s *subsonicMediaProvider) CanShareArtists() bool {
+	// TODO: Change to true when we decide to allow sharing artists, in case an OpenSubsonic extension
+	//       is approved to share artists in addition to albums and tracks.
+	return false
+}
+
 func (s *subsonicMediaProvider) DownloadTrack(trackID string) (io.Reader, error) {
 	return s.client.Download(trackID)
 }