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/tidal/tidalservice.h

@@ -30,6 +30,7 @@
 #include <QPair>
 #include <QList>
 #include <QString>
+#include <QStringList>
 #include <QUrl>
 #include <QNetworkReply>
 #include <QTimer>
@@ -61,7 +62,6 @@ class TidalService : public InternetService {
   static const Song::Source kSource;
 
   void ReloadSettings();
-  QString CoverCacheDir();  
 
   void Logout();
   int Search(const QString &query, InternetSearch::SearchType type);
@@ -69,6 +69,8 @@ class TidalService : public InternetService {
 
   const int max_login_attempts() { return kLoginAttempts; }
 
+  Application *app() { return app_; }
+
   const bool oauth() { return oauth_; }
   QString client_id() { return client_id_; }
   QString api_token() { return api_token_; }
@@ -132,6 +134,7 @@ class TidalService : public InternetService {
  private slots:
   void StartAuthorisation();
   void AuthorisationUrlReceived(const QUrl &url);
+  void HandleLoginSSLErrors(QList<QSslError> ssl_errors);
   void AccessTokenRequestFinished(QNetworkReply *reply);
   void SendLogin();
   void HandleAuthReply(QNetworkReply *reply);
@@ -160,7 +163,7 @@ class TidalService : public InternetService {
   typedef QList<EncodedParam> EncodedParamList;
 
   void SendSearch();
-  QString LoginError(QString error, QVariant debug = QVariant());
+  void LoginError(const QString &error = QString(), const QVariant &debug = QVariant());
 
   static const char *kApiTokenB64;
   static const char *kOAuthUrl;
@@ -240,6 +243,8 @@ class TidalService : public InternetService {
 
   QList<TidalStreamURLRequest*> stream_url_requests_;
 
+  QStringList login_errors_;
+
 };
 
 #endif  // TIDALSERVICE_H