[PATCH v3 0/4] MR322: winex11.drv: Preparation for nulldrv display modes.

[Rémi Bernon (@rbernon)]

The idea is to have a `add_mode` manager callback and enumerate adapter modes when updating display devices. Then the modes would be read from the registry and cached with the adapters and monitors, allowing us to move more things to win32u.

This MR is a preparation towards that, moving the `winex11` settings handler to display.c, and making sure we do not enumerate display modes before they have been initialized or while the list is being built.

--
  v3: winex11.drv: Avoid requesting current mode in X11DRV_desktop_get_modes.
      winex11.drv: Merge settings.c into display.c.
      winex11.drv: Use nameless structs and unions in settings.c.
      winex11.drv: Rename display settings handlers to settings_handler.
 
https://gitlab.winehq.org/wine/wine/-/merge_requests/322