[macOS] Quick Controls: MenuBar, Menu, MenuItem - add possibility to create native menus on Mac.

It's totally possible to create a QML application that is not using QtWidgets.
However, the only way to make a native application menu now is to use QtWidgets (directly or via Qt.labs.platform, that also depends on it).

Please, add an option to set a native menu to [application] windows, and to set native menu roles (https://doc.qt.io/qt-6/qml-qt-labs-platform-menuitem.html#role-prop such as MenuItem.AboutRole, MenuItem.PreferencesRole).

The QtWidgets module is frozen now. And for apps that doesn't use it, it would be great to not link to it at all, and to not ship it, but to have native menubar (which is pretty much expected at any Mac app).