Making all the windows handled by the driver to be either GL/VK client surfaces, or top-level windows. This avoids leaking host windows into the Win32 space, and makes it possible to get rid of some remaining NtUserMapWindowPoints in `map_event_coords` for mouse input.
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v6: winex11: Get rid of the now unnecessary foreign windows.
winex11: Generate relative ConfigureNotify on parent ConfigureNotify events.
winex11: Use the new host windows to register foreign window events.
winex11: Keep track of the host windows children window rects.
winex11: Keep track of the host windows relative rects.
winex11: Keep track of the host window children of interest.
winex11: Create host windows recursively up to root_window.
winex11: Introduce a new struct host_window for host-only windows.
https://gitlab.winehq.org/wine/wine/-/merge_requests/6649