KCM KWin Manage default Highlight indicator for settings not handled by KCModule

For the following KCM :
* KWin Options
* KWin Screen Edges
* KWin Tabbox

KCModule introduce an indicator to show which settings have changed from
default value. Unfortunately some KCM have settings' states which are not managed
automatically by the KCModule thus we have to handle it manually.

see frameworks/kconfigwidgets!9