Fix(clan.nix): create public attributes from 'clan', dont expose them from clanInternals

ClanInternals is already exposed at the toplevel the API can access anything
This also deduplicated 'templates' and 'modules' into 'clan.modules' and 'clan.templates' repsectively
Only this one path is its source

lib/build-clan/module.nix

@@ -150,7 +150,9 @@ in
             inventory._inventoryFile = file;
           }
         ];
-        inventory = inventoryLoaded;
+        # Weirdly this works only if it is a function
+        # This seems to be a bug in nixpkgs
+        inventory = _: lib.setDefaultModuleLocation file inventoryLoaded;
       }
     )
     {