WIP: Send only current wl_output mode
Non-current output modes were deprecated due to various reasons, e.g. it's not possible to remove some nodes; two modes can have the same resolution and the refresh rate but different flags, but wl_output.mode fails to communicate that properly; the usefulness of non-current modes is questionable. For more details, please refer to [1].
[1] https://gitlab.freedesktop.org/wayland/wayland/-/issues/92
WIP as I need to rebase it once !207 (merged) lands.