feat(buildInventory): move instance resolution into buildInventory

Such that buildClan doesn't have to compose the results
buildInventory should be more self contained. But it is NOT meant a
public API! use buildClan argument 'inventory' instead

lib/inventory/build-inventory/builder/interface.nix

@@ -9,6 +9,9 @@ in
     directory = mkOption {
       type = types.path;
     };
+    distributedServices = mkOption {
+      type = types.raw;
+    };
     inventory = mkOption {
       type = types.raw;
     };