SLCI Product restructure

- Append the variant selection template when the bag icon is click
- Add out-of-stock class to each variant options if the variant is out of stock
- Create a function that will replace the current selection with the new variant selection base on selected color
- Create a function that will toggle change the variant id as value on hidden input
- Create a function with parameter of variant id using /add/cart.js endpoint of shopify
- Create a function that will check if the selected variant is already on the cart
- Create a function that will update the add to cart button if OOS, already in cart or ready to be added