feat(prerender): add 'Neuheiten' category and update data fetching logic

- Introduce a new category 'Neuheiten' to the rendering process by appending it to the existing categories.
- Modify the data fetching logic to handle the 'neu' category ID correctly.
- Enhance the UI by adding a button for the 'Neuheiten' category in the CategoryList component, complete with styling and internationalization support.

prerender/data-fetching.cjs

@@ -39,7 +39,7 @@ const fetchCategoryProducts = (socket, categoryId) => {
 
     socket.emit(
       "getCategoryProducts",
-      { full:true, categoryId: parseInt(categoryId) },
+      { full:true, categoryId: categoryId === "neu" ? "neu" : parseInt(categoryId) },
       (response) => {
         clearTimeout(timeout);
         if (response && response.products !== undefined) {