add kleiner (wg raspi) configuration

nix/flake.nix

@@ -36,6 +36,15 @@
           nur.modules.nixos.default
         ];
       };
+      kleiner = nixpkgs.lib.nixosSystem {
+        specialArgs = {
+          inherit inputs outputs;
+          hostname = "kleiner";
+        };
+        modules = [
+          ./kleiner.nix
+        ];
+      };
     };
   };
 }