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/kdeclarative.nix

@@ -8,8 +8,9 @@ mkDerivation {
   name = "kdeclarative";
   meta = { maintainers = [ lib.maintainers.ttuegel ]; };
   nativeBuildInputs = [ extra-cmake-modules ];
-  propagatedBuildInputs = [
-    epoxy kconfig kglobalaccel kguiaddons ki18n kiconthemes kio kpackage
-    kwidgetsaddons kwindowsystem qtdeclarative
+  buildInputs = [
+    epoxy kglobalaccel kguiaddons ki18n kiconthemes kio kwidgetsaddons
+    kwindowsystem
   ];
+  propagatedBuildInputs = [ kconfig kpackage qtdeclarative ];
 }