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.

astro-i18next.config.mjs

@@ -0,0 +1,57 @@
+/** @type {import('astro-i18next').AstroI18nextConfig} */
+export default {
+  defaultLocale: "en",
+  locales: ["en", "nl", "it"],
+  namespaces: ["translation"],
+  defaultNamespace: "translation",
+  load: ["server", "client"],
+  i18nextServer: {
+    debug: true,
+    initImmediate: false,
+    supportedLngs: ["en", "nl", "it"],
+    fallbackLng: "en",
+    ns: ["translation"],
+    defaultNS: "translation",
+    resources: {
+      en: {
+        translation: () => import("../public/locales/en/translation.json")
+      },
+      nl: {
+        translation: () => import("../public/locales/nl/translation.json")
+      },
+      it: {
+        translation: () => import("../public/locales/it/translation.json")
+      }
+    }
+  },
+  i18nextClient: {
+    debug: false,
+    supportedLngs: ["en", "nl", "it"],
+    fallbackLng: "en",
+    ns: ["translation"],
+    defaultNS: "translation"
+  },
+  routes: {
+    en: {
+      about: 'about',
+      services: 'services',
+      contact: 'contact',
+      privacy: 'privacy',
+      terms: 'terms'
+    },
+    nl: {
+      about: 'over-ons',
+      services: 'diensten',
+      contact: 'contact',
+      privacy: 'privacy',
+      terms: 'voorwaarden'
+    },
+    it: {
+      about: 'chi-siamo',
+      services: 'servizi',
+      contact: 'contatti',
+      privacy: 'privacy',
+      terms: 'termini'
+    }
+  }
+};