hosts/ni: convert to systemd-networkd for network config

I thought it is pretty neat. Also, I've created a bond interface for the
network devices.

hosts/ni/hardware-configuration.nix

@@ -25,9 +25,50 @@
 
   swapDevices = [{ label = "swap"; }];
 
-  networking.useDHCP = false;
+  networking = {
-  networking.interfaces.enp1s0.useDHCP = true;
+    useDHCP = false;
-  networking.interfaces.wlp2s0.useDHCP = true;
+    usePredictableInterfaceNames = true;
+    useNetworkd = true;
+
+    # We're using networkd to configure so we're disabling this
+    # service.
+    dhcpcd.enable = false;
+  };
+
+  # Enable systemd-resolved. This is mostly setup by `systemd.network.enable`
+  # by we're being explicit just to be safe.
+  services.resolved = {
+    enable = true;
+    llmnr = "true";
+  };
+
+  # Combining my ethernet and wireless network interfaces.
+  systemd.network = {
+    enable = true;
+    netdevs."40-bond1" = {
+      netdevConfig = {
+        Name = "bond1";
+        Kind = "bond";
+      };
+    };
+
+    networks = {
+      "40-bond1" = {
+        matchConfig.Name = "bond1";
+        networkConfig.DHCP = "yes";
+      };
+
+      "40-bond1-dev1" = {
+        matchConfig.Name = "enp1s0";
+        networkConfig.Bond = "bond1";
+      };
+
+      "40-bond1-dev2" = {
+        matchConfig.Name = "wlp2s0";
+        networkConfig.Bond = "bond1";
+      };
+    };
+  };
 
   powerManagement.cpuFreqGovernor = lib.mkDefault "powersave";
   hardware.cpu.intel.updateMicrocode = lib.mkDefault true;