[kcms/keys] Highlight changed settings

Manual implementation of change highlighting as done automatically in other kcms. Highlighted items include: Collpased action delegates whose active key sequences are different from the default, in the expaned state unset checkboxes for default key sequences and keysequenceitems for added shortcuts are highlighted. Finally in the components list, delegates who contain at least one action that is not in a default state are higlighted in the same style as config modules in the system settings sidebar.

Needs: frameworks/kdeclarative!18 (merged) and breeze!27 (merged)