kdeFrameworks: fixup inputs and outputs

- Reduce environment pollution with a separate $bin output containing programs,
  plugins, and shared data. Libraries remain in $out and are not installed into
  the environment.
- Only propagate build inputs as required.

pkgs/development/libraries/kde-frameworks/knotifications.nix

@@ -10,7 +10,7 @@ mkDerivation {
   name = "knotifications";
   meta = { maintainers = [ lib.maintainers.ttuegel ]; };
   nativeBuildInputs = [ extra-cmake-modules qttools ];
-  propagatedBuildInputs = [
+  buildInputs = [
     kcodecs kconfig kcoreaddons kwindowsystem libdbusmenu phonon qtx11extras
   ];
 }