Improve album cover searching and cover manager, use HttpStatusCodeAttribute and QSslError for services

- Improve album cover manager
- Change art_automatic and art_manual to QUrl
- Refresh collection album covers when new album covers are fetched
- Fix automatic album cover searching for local files outside of the collection
- Make all Json services check HttpStatusCodeAttribute
- Show detailed SSL errors for Subsonic, Tidal and Qobuz

src/core/macsystemtrayicon.mm

@@ -28,6 +28,7 @@
 #include <QApplication>
 #include <QAction>
 #include <QIcon>
+#include <QUrl>
 #include <QtDebug>
 
 #include <AppKit/NSMenu.h>
@@ -205,6 +206,6 @@ void MacSystemTrayIcon::ClearNowPlaying() {
   p_->ClearNowPlaying();
 }
 
-void MacSystemTrayIcon::SetNowPlaying(const Song& song, const QString& image_path) {
+void MacSystemTrayIcon::SetNowPlaying(const Song& song, const QUrl& cover_url) {
   p_->ShowNowPlaying(song.artist(), song.PrettyTitle());
 }