feat: Add the launcher root folder to the Folders menu

Signed-off-by: Redson <redson@riseup.net>

launcher/ui/MainWindow.h

@@ -112,6 +112,8 @@ private slots:
 
     void on_actionViewInstanceFolder_triggered();
 
+    void on_actionViewLauncherRootFolder_triggered();
+
     void on_actionViewSelectedInstFolder_triggered();
 
     void refreshInstances();