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/index.d.mts

@@ -0,0 +1,59 @@
+import * as i18nextMod from './index.js';
+import type { $Dictionary } from './typescript/helpers.js';
+
+import type { DefaultNamespace, Namespace } from './typescript/options.js';
+
+export type WithT<Ns extends Namespace = DefaultNamespace> = i18nextMod.WithT<Ns>;
+export type Interpolator = i18nextMod.Interpolator;
+export type ResourceStore = i18nextMod.ResourceStore;
+export type Formatter = i18nextMod.Formatter;
+export type Services = i18nextMod.Services;
+export type ModuleType = i18nextMod.ModuleType;
+export type Module = i18nextMod.Module;
+export type CallbackError = i18nextMod.CallbackError;
+export type ReadCallback = i18nextMod.ReadCallback;
+export type MultiReadCallback = i18nextMod.MultiReadCallback;
+export type BackendModule<TOptions = object> = i18nextMod.BackendModule<TOptions>;
+export type LanguageDetectorModule = i18nextMod.LanguageDetectorModule;
+export type LanguageDetectorAsyncModule = i18nextMod.LanguageDetectorAsyncModule;
+export type PostProcessorModule = i18nextMod.PostProcessorModule;
+export type LoggerModule = i18nextMod.LoggerModule;
+export type I18nFormatModule = i18nextMod.I18nFormatModule;
+export type FormatterModule = i18nextMod.FormatterModule;
+export type ThirdPartyModule = i18nextMod.ThirdPartyModule;
+export type Modules = i18nextMod.Modules;
+export type Newable<T> = i18nextMod.Newable<T>;
+export type NewableModule<T extends Module> = i18nextMod.NewableModule<T>;
+export type Callback = i18nextMod.Callback;
+export type ExistsFunction<
+  TKeys extends string = string,
+  TInterpolationMap extends object = $Dictionary,
+> = i18nextMod.ExistsFunction<TKeys, TInterpolationMap>;
+export type CloneOptions = i18nextMod.CloneOptions;
+
+export type * from './typescript/options.js';
+export type * from './typescript/t.js';
+
+export interface CustomInstanceExtensions {}
+
+// eslint-disable-next-line @typescript-eslint/naming-convention
+export interface i18n extends i18nextMod.i18n, CustomInstanceExtensions {}
+
+declare const i18next: i18n;
+export default i18next;
+
+export const createInstance: i18n['createInstance'];
+
+export const dir: i18n['dir'];
+export const init: i18n['init'];
+export const loadResources: i18n['loadResources'];
+export const reloadResources: i18n['reloadResources'];
+export const use: i18n['use'];
+export const changeLanguage: i18n['changeLanguage'];
+export const getFixedT: i18n['getFixedT'];
+export const t: i18n['t'];
+export const exists: i18n['exists'];
+export const setDefaultNamespace: i18n['setDefaultNamespace'];
+export const hasLoadedNamespace: i18n['hasLoadedNamespace'];
+export const loadNamespaces: i18n['loadNamespaces'];
+export const loadLanguages: i18n['loadLanguages'];