Revert "nixos: Multiple service instances, apply to nginx. See #6784"

This reverts commit 7ef59c4fe2.

Wrong push! Sorry!

lib/types.nix

@@ -227,19 +227,4 @@ rec {
 
   };
 
-  mkMultiInstance = path: args: f:
-    let
-      def = f (args // { name = "default"; config = getAttrFromPath path args.config; });
-    in {
-      options = setAttrByPath path (def.options // {
-        instances = mkOption {
-          type = types.attrsOf (types.submodule f);
-          default = {};
-          description = "Additional instances of this service";
-        };
-      });
-
-      config = def.config;
-    };
-
 }