Actually apply systemd-networkd configuration

Also disable networking.* options

hosts/nixos-server-test/default.nix

@@ -4,10 +4,8 @@
   imports =
     [
       ../../modules/nix.nix
-      ../../modules/network-server.nix
       ../../modules/locale.nix
       ../../modules/server-cli.nix
-      ../../modules/nix.nix
       ../../modules/sshd.nix
       # Include the results of the hardware scan.
       ./hardware-configuration.nix
@@ -39,6 +37,57 @@
   services.proxmox-ve = {
     enable = true;
     ipAddress = "192.168.122.42";
+
+    # Make vmbr0 bridge visible in Proxmox web interface
+    bridges = [ "vmbr0" ];
+  };
+
+  networking.useDHCP = false;
+
+  systemd.network = {
+    enable = true;
+
+    links."10-wan" = {
+        matchConfig.Path = "pci-0000:01:00.0";
+        linkConfig.Name = "wan";
+    };
+
+    networks."10-wan" = {
+      matchConfig.Name = "enp1s0";
+      networkConfig = {
+        # start a DHCP Client for IPv4 Addressing/Routing
+        DHCP = "ipv4";
+        # accept Router Advertisements for Stateless IPv6 Autoconfiguraton (SLAAC)
+        IPv6AcceptRA = true;
+      };
+      # make routing on this interface a dependency for network-online.target
+      linkConfig.RequiredForOnline = "routable";
+    };
+
+
+    # Actually set up the vmbr0 bridge
+    networks."10-lan" = {
+      matchConfig.Name = [ "ens18" ];
+      networkConfig = {
+        Bridge = "vmbr0";
+      };
+    };
+
+    netdevs."vmbr0" = {
+      netdevConfig = {
+        Name = "vmbr0";
+        Kind = "bridge";
+      };
+    };
+
+    networks."10-lan-bridge" = {
+      matchConfig.Name = "vmbr0";
+      networkConfig = {
+        IPv6AcceptRA = true;
+        DHCP = "ipv4";
+      };
+      linkConfig.RequiredForOnline = "routable";
+    };
   };
 
   # This option defines the first version of NixOS you have installed on this particular machine,