Add package function-schema and module-schema. Add check for module jsonschema.

lib/default.nix

@@ -6,6 +6,6 @@
 }:
 {
   jsonschema = import ./jsonschema { inherit lib; };
-
+  modules = import ./description.nix { inherit clan-core; };
   buildClan = import ./build-clan { inherit clan-core lib nixpkgs; };
 }