Summary:
Adds a new framebuffer implementation, which uses xdg-desktop-portal to support remote
desktop on Wayland and uses PipeWire to deliver the screen content. So far only mouse
support is implemented, because keyboard support is missing on KWin side.

Reviewers: Kanedias, romangg

Reviewed By: Kanedias

Subscribers: asturmlechner, pino, ngraham, romangg

Differential Revision: https://phabricator.kde.org/D20402