Now that KDE Connect has moved to Qt6 only since https://invent.kde.org/network/kdeconnect-kde/-/merge_requests/621 we can remove the old KF5 plasmoid.
Currently the plasmoid is still written for KF5/Plasma 5, and in addition it also still uses PlasmaComponents2 stuff, which has been removed in KF6/Plasma 6. So, this is an attempt to port the plasmoid so that it works in Plasma 6. BUG: 476389
It allows to use other paired devices as external displays transparently.