[sets] Remove KDE SC 4 master branch

KDE SC 4,14 is the last release and master opened for frameworks
migration by upstream.
[Documentation] Remove KDE SC 4 master branch keywords

KDE SC 4,14 is the last release and master opened for frameworks
migration by upstream.
[kde-base] Remove KDE SC 4 master branch

KDE SC 4,14 is the last release and master opened for frameworks migration by
upstream.

Package-Manager: portage-2.2.11-r1