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/deepmerge/index.d.ts

@@ -0,0 +1,20 @@
+declare function deepmerge<T>(x: Partial<T>, y: Partial<T>, options?: deepmerge.Options): T;
+declare function deepmerge<T1, T2>(x: Partial<T1>, y: Partial<T2>, options?: deepmerge.Options): T1 & T2;
+
+declare namespace deepmerge {
+	export interface Options {
+		arrayMerge?(target: any[], source: any[], options?: ArrayMergeOptions): any[];
+		clone?: boolean;
+		customMerge?: (key: string, options?: Options) => ((x: any, y: any) => any) | undefined;
+		isMergeableObject?(value: object): boolean;
+	}
+	export interface ArrayMergeOptions {
+		isMergeableObject(value: object): boolean;
+		cloneUnlessOtherwiseSpecified(value: object, options?: Options): object;
+	}
+
+	export function all (objects: object[], options?: Options): object;
+	export function all<T> (objects: Partial<T>[], options?: Options): T;
+}
+
+export = deepmerge;