nixos-server: switch to networkd for interface management

hosts/shared/nixos-server.nix

@@ -51,13 +51,50 @@ in
   };
 
   networking = {
+    useNetworkd = true;
+
     firewall = {
       trustedInterfaces = [ "br0" ];
       allowedTCPPorts = [ 22 ];
     };
+  };
 
-    bridges.br0.interfaces = [ "eno1" ];
-    interfaces.br0.useDHCP = true;
+  systemd.network = {
+    enable = true;
+
+    netdevs = {
+      "30-br0" = {
+        netdevConfig = {
+          Kind = "bridge";
+          Name = "br0";
+          MACAddress = "none";
+        };
+      };
+    };
+
+    networks = {
+      "30-eno1" = {
+        name = "eno1";
+        bridge = [ "br0" ];
+      };
+
+      "30-br0" = {
+        name = "br0";
+        DHCP = "yes";
+      };
+    };
+
+    links = {
+      "30-br0" = {
+        matchConfig = {
+          OriginalName = "br0";
+        };
+
+        linkConfig = {
+          MACAddressPolicy = "none";
+        };
+      };
+    };
   };
 
   time.timeZone = "America/New_York";