Use the RemoteDesktop portal to input from wayland

Cross-desktop approach to moving the cursor remotely on wayland. Should work on X11 too, so we can consider drop the other one as well.

It adds support for receiving full text as well, which didn't use to be possible.

WIP because:

• it depends on plasma/xdg-desktop-portal-kde!131 (merged)
• we should find a way for Plasma (and others) to remember the setting, otherwise we are prompted every time.