GtkModelButton: Add a menu-name property
GtkModelButton: Add a menu-name property

Add a menu-name property and use it in a default implementation
of ::clicked to switch menus if we are inside a stack. This means
GtkModelButton is no longer entirely generic, but rather expects
to be used inside a GtkPopoverMenu. It still works in other contexts
too, of course.

ahodesuka/gtk,grubersjoe/adwaita,alexlarsson/gtk,jigpu/gtk,Adamovskiy/gtk,jadahl/gtk,Adamovskiy/gtk,alexlarsson/gtk,ahodesuka/gtk,Adamovskiy/gtk,alexlarsson/gtk,alexlarsson/gtk,chergert/gtk,Adamovskiy/gtk,Adamovskiy/gtk,davidgumberg/gtk,grubersjoe/adwaita,davidgumberg/gtk,Lyude/gtk-,chergert/gtk,jigpu/gtk,Lyude/gtk-,ahodesuka/gtk,chergert/gtk,Lyude/gtk-,Adamovskiy/gtk,jigpu/gtk,chergert/gtk,Adamovskiy/gtk,jadahl/gtk,Lyude/gtk-,jigpu/gtk,Lyude/gtk-,alexlarsson/gtk,alexlarsson/gtk,davidgumberg/gtk,ahodesuka/gtk,jigpu/gtk,jadahl/gtk,chergert/gtk,grubersjoe/adwaita,chergert/gtk,Lyude/gtk-,grubersjoe/adwaita,chergert/gtk,jigpu/gtk,jigpu/gtk,alexlarsson/gtk,Adamovskiy/gtk,jadahl/gtk,davidgumberg/gtk,jadahl/gtk,ahodesuka/gtk,davidgumberg/gtk,ahodesuka/gtk,jigpu/gtk,grubersjoe/adwaita,alexlarsson/gtk,chergert/gtk,davidgumberg/gtk,jadahl/gtk,davidgumberg/gtk,Lyude/gtk-,davidgumberg/gtk,grubersjoe/adwaita,jadahl/gtk,ahodesuka/gtk,jadahl/gtk,Lyude/gtk-,ahodesuka/gtk,grubersjoe/adwaita,grubersjoe/adwaita