added display of vpn containers and services on the settings page

- added PageSettingsData and implementation of 'remove all containers'  button

client/ui/models/containers_model.h

@@ -48,6 +48,8 @@ public slots:
     void setCurrentlyInstalledContainerIndex(int index);
     int getCurrentlyInstalledContainerIndex();
 
+    void removeAllContainers();
+
 protected:
     QHash<int, QByteArray> roleNames() const override;