When the locale is changed then it should be propagated to the the controls in the ApplicationWindow, but Label and TextField are not seen as controls

When the locale is changed then it should be propagated to the the controls in the ApplicationWindow, but Label and TextField are not seen as controls. This is because they are based on QQuickText and as a result it has no locale property and does not get updated.

Adding an explicit property in this case would make it possible for them to adapt to locale changes without having to try to depend on the ApplicationWindow's locale property.