Add support for the protocol used by Gnome Shell

Gnome Shell has a built in OSK. Fingerboard currently only works on Phosh because of the used protocols. It would be nice if it could be used on Gnome Shell too. Here is a link to the code of Gnomes OSK:
https://gitlab.gnome.org/GNOME/gnome-shell/-/blob/main/js/ui/keyboard.js