Draft: wayland: Maximize window if it doesn't fit the placement area

If the window is too large for the placement area, maximize it. Note that there is a proposal upstream to extend the xdgs-shell protocol with an event that can be used by the compositor to tell the client how big the window can be. But it's worth to have this change in meanwhile, until the relevant protocol change lands and all clients are ported to it.

https://gitlab.freedesktop.org/wayland/wayland-protocols/-/merge_requests/41