nixos-module/server/network: enable STP and decrease forward_delay for bridges

nix/nixos-module/server/network.nix

@@ -49,9 +49,16 @@ in
     } // (
       builtins.foldl' (result: net: result // {
         # Bridges are named just like the corresponding net.
-        "${net}".netdevConfig = {
-          Kind = "bridge";
-          Name = "${net}";
+        "${net}" = {
+          netdevConfig = {
+            Kind = "bridge";
+            Name = "${net}";
+          };
+          extraConfig = ''
+            [Bridge]
+            ForwardDelaySec=2
+            STP=true
+          '';
         };
       }) {} bridgeNets
     ) // (