Add the Qt window module as an alternative to the SDL2 module

Att the Qt window module as an alternative to the SDL2 module

Description is TBD

src/module/qt_window/qthelper.hh

@@ -78,6 +78,7 @@ node_to_variant(const mpv_node *node)
     case MPV_FORMAT_NODE:
     case MPV_FORMAT_BYTE_ARRAY: return QVariant();
     }
+    LOG_UNREACHABLE;
 }
 
 struct node_builder {