Input Capture Support

[sithlord48]

Problem

Input capture is need to support applications like input-leap , and deskflow (formally synergy).

Support has added in the KDE and GNOME portals.
I am raising this issue in portals without support.

The portal should also allow input capture access to the clipboard.

Proposal

Add Support for Input Capture Portal ,Allow input capture access to the clipboard

Prior Art (Optional)

Both KDE and GNOME portals