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