Split from https://gitlab.winehq.org/wine/wine/-/merge_requests/576, for which I'll then add modes sorting, and move support for stretched / interlaced modes from winemac to win32u.
-- v2: win32u: Only read/write valid mode fields from/to the registry. win32u: Use current mode position if desired mode doesn't specify it. win32u: Always copy devmode in validate_display_settings. win32u: Read registry or current mode when validation needs it. win32u: Do not keep display modes driver extra in the registry.