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/kwayland.nix

@@ -1,5 +1,5 @@
 {
-  mkDerivation, lib,
+  mkDerivation, lib, propagateBin,
   extra-cmake-modules,
   qtbase, wayland
 }:
@@ -11,6 +11,7 @@ mkDerivation {
     broken = builtins.compareVersions qtbase.version "5.6.0" < 0;
   };
   nativeBuildInputs = [ extra-cmake-modules ];
-  buildInputs = [ qtbase ];
-  propagatedBuildInputs = [ wayland ];
+  buildInputs = [ wayland ];
+  propagatedBuildInputs = [ qtbase ];
+  setupHook = propagateBin; # XDG_CONFIG_DIRS
 }