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/kitemmodels.nix

@@ -12,4 +12,5 @@ mkDerivation {
   };
   nativeBuildInputs = [ extra-cmake-modules ];
   propagatedBuildInputs = [ qtbase ];
+  outputs = [ "out" "dev" ];
 }