Put KCModuleProxy into a QScrollArea the same way SystemSettings does
This should make kcmshell and other users of KCMultiDialog
a bit more friendly to small screens
However, this assumes that KCMs don't have their own scrollbars
(at least sytsemsettings ones don't) and preferably have a size hint
(only a few or none actually have; at least kscreen needs patching)
BUG: 354227
Also, reorder headers of the unit