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/cross-fetch/dist/node-polyfill.js

@@ -0,0 +1,11 @@
+const fetchNode = require('./node-ponyfill')
+
+if (!global.fetch) {
+  const fetch = fetchNode.fetch.bind({})
+
+  global.fetch = fetch
+  global.fetch.polyfill = true
+  global.Response = fetchNode.Response
+  global.Headers = fetchNode.Headers
+  global.Request = fetchNode.Request
+}