Use one instance of NetworkAccessManager

src/core/application.h

@@ -41,6 +41,7 @@ class TagReaderClient;
 class Database;
 class DeviceFinders;
 class Player;
+class NetworkAccessManager;
 class SCollection;
 class CollectionBackend;
 class CollectionModel;
@@ -74,6 +75,7 @@ class Application : public QObject {
   Database *database() const;
   TaskManager *task_manager() const;
   Player *player() const;
+  NetworkAccessManager *network() const;
   DeviceFinders *device_finders() const;
 #ifndef Q_OS_WIN
   DeviceManager *device_manager() const;