i2pd: add yggdrasil settings

nixos/modules/services/networking/i2pd.nix

@@ -158,6 +158,10 @@ let
       (sec "addressbook")
       (strOpt "defaulturl" cfg.addressbook.defaulturl)
     ] ++ (optionalEmptyList "subscriptions" cfg.addressbook.subscriptions)
+      ++ [
+      (sec "meshnets")
+      (boolOpt "yggdrasil" cfg.yggdrasil.enable)
+    ] ++ (optionalNullString "yggaddress" cfg.yggdrasil.address)
       ++ (flip map
       (collect (proto: proto ? port && proto ? address) cfg.proto)
       (proto: let protoOpts = [
@@ -546,6 +550,17 @@ in
         '';
       };
 
+      yggdrasil.enable = mkEnableOption "Yggdrasil";
+
+      yggdrasil.address = mkOption {
+        type = with types; nullOr str;
+        default = null;
+        description = ''
+          Your local yggdrasil address. Specify it if you want to bind your router to a
+          particular address.
+        '';
+      };
+
       proto.http = (mkEndpointOpt "http" "127.0.0.1" 7070) // {
 
         auth = mkEnableOption "Webconsole authentication";