Add support for InputCapture portal

[theofficialgman]

InputCapture portal spec has been finalized and merged in xdg-desktop-portal flatpak/xdg-desktop-portal#714
It has also been implemented and merged into xdg-desktop-portal-gnome https://gitlab.gnome.org/GNOME/xdg-desktop-portal-gnome/-/merge_requests/61
This isssue is a request that it be implemented in xdg-desktop-portal-kde

This portal interface, alongside implementing the RemoteDesktop portal #2, is important for Barrier/Input Leap/Synergy usecase

[columbarius]

This requires support for libei from compositors and a wayland protocol to relay the setup information.

[PedroHLC]

Last week, I finally tried KVMing from input-leap (in GNOME) to waynergy (in Sway), it wasn't as perfect as Synergy was for X11⇾X11, but it was good enough.

I did try to use #263, but it doesn't have the ConnectToEI bits and wasn't enough for input-leap to work as a client (but it does have enough of #2 to work with KDE Connect, as I stated there before).

Waynergy is fine for this scenario, but I'd prefer not to use GNOME on any of these machines.

Sad to see it stalled here, Synergy exists for 22 years now and its UX is battle-proved, while input-leap through libei provides that wonderfully.

[sithlord48]

Hello the current libei has support and input-capture is working in the kde and gnome portals.

Is there any chance of this one being added ?