Add internationalization support with astro-i18next integration

- Implemented astro-i18next for multi-language support, including English, Dutch, and Italian.
- Configured default locale and language fallback settings.
- Defined routes for localized content in the configuration.
- Updated package.json and package-lock.json to include new dependencies for i18next and related plugins.

node_modules/@babel/runtime/helpers/classPrivateFieldSet2.js

@@ -0,0 +1,5 @@
+var assertClassBrand = require("./assertClassBrand.js");
+function _classPrivateFieldSet2(s, a, r) {
+  return s.set(assertClassBrand(s, a), r), r;
+}
+module.exports = _classPrivateFieldSet2, module.exports.__esModule = true, module.exports["default"] = module.exports;