[kde-frameworks/kf-env] New package

Installs environment file for all kf based applications/window manager/desktop
environments. The environment file is named 78kf and installed to /etc/env.d/.
It has a higher number than KDE SC 4 based env file from kde-base/kde-env. This
should guarantee that old QT_PLUGIN_PATH is not overridden. This needs to be
tested.

Package-Manager: portage-2.2.10
[eclass] Add kde-frameworks/kf-env to RDEPEND