port wayland module to cli wayland-info

this completely gets rid of the dependency on kwayland and, like all other cli modules, gets rid of all the code and the associated maintenance burden associated with it. instead the entire shebang is outsourced to the new wayland-info tool from FDO's wayland-utils

seeing as the wayland kcm is (and always was) utterly pointless outside wayland we are now also setting X-KDE-OnlyShowOnQtPlatforms to wayland, thereby having it hidden on x11