It's not working properly currently!!!

Add functionality to shopping cart feature in cart.js

Implemented `addToCartClickHandler` function in cart.js for handling cart item additions. This feature enables users to add items from product select options to the cart, specify the quantity, and delete items as necessary. The Add to Cart button is moved to each new item line for better UX. In this commit, prevent default behaviour on form submission and set up an async POST request using Fetch API to send the cart information to the server. This update improves the shopping cart usability and efficiency in processing cart data.