NOISSUE add option to open global settings from instance settings

This should hopefully giude people towards using the right thing.

application/pages/instance/InstanceSettingsPage.h

@@ -66,6 +66,8 @@ private slots:
 
     void checkerFinished();
 
+    void globalSettingsButtonClicked(bool checked);
+
 private:
     Ui::InstanceSettingsPage *ui;
     BaseInstance *m_instance;