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/i18next-http-backend/esm/getFetch.cjs

@@ -0,0 +1,13 @@
+var fetchApi = typeof fetch === 'function' ? fetch : undefined
+if (typeof global !== 'undefined' && global.fetch) {
+  fetchApi = global.fetch
+} else if (typeof window !== 'undefined' && window.fetch) {
+  fetchApi = window.fetch
+}
+
+if (typeof require !== 'undefined' && typeof window === 'undefined') {
+  var f = fetchApi || require('cross-fetch')
+  if (f.default) f = f.default
+  exports.default = f
+  module.exports = exports.default
+}