* move ksplash KCM module to kcontrol sub-directory, ksplash it
build always and there is no reason to keep it out of the
kcontrol directory holding all major KCM modules
* merge some sub-category modules into other major categories
almost the same way it is done in KDE5 as it makes much more
sense and users do not have to go to in-and-out of
sub-categories to configure the overall desktop appearance
- application-appearance -> desktop-appearance
- window-behaviour -> workspace-behavior
- workspace-appearance-and-behavior -> workspace-behaviour
