Add systemd-networkd system module

system/modules/systemd-networkd/options.nix

@@ -0,0 +1,59 @@
+{
+  lib,
+  mylib,
+  ...
+}:
+with lib;
+with mylib.modules; {
+  enable = mkEnableOpt "Systemd Network Configuration";
+
+  hostname = mkOption {
+    type = types.str;
+    description = "The System's Hostname";
+    example = ''
+      "Nixinator"
+    '';
+  };
+
+  networks = mkOption {
+    type = types.attrSet;
+    default = {};
+    description = "Systemd-Networkd Networks";
+    example = ''
+      {
+        "50-ether" = {
+          [...]
+        };
+      }
+    '';
+  };
+
+  wireguard-tunnels = mkOption {
+    type = types.attrSet;
+    default = {};
+    description = "Wireguard VPN Tunnels";
+    example = ''
+      wg0-de-115 = {
+        [...]
+      };
+    '';
+  };
+
+  allowedTCPPorts = mkOption {
+    type = types.list;
+    default = [];
+    description = "Open TCP Ports in the Firewall";
+    example = ''
+      [22 80 443]
+    '';
+  };
+
+  allowedUDPPorts = mkOption {
+    type = types.list;
+    default = [];
+    description = "Open UDP Ports in the Firewall";
+    example = ''
+      [22 80 443]
+    '';
+  };
+}