Added automatic language switching option to debugger settings

Additionally, hiding of debugger menu entries was done as most of
them are irrelevant for QML debugging.

src/plugins/debugger/debuggerplugin.h

@@ -119,6 +119,7 @@ private slots:
     void attachCmdLine();
 
     void enableReverseDebuggingTriggered(const QVariant &value);
+    void languageChanged(const QString &debuggerLanguage);
 
 private:
     void readSettings();