Implement finalization of the order in cart template

[Ramin-RX7]

In the cart template, below the cart items, price and details must be shown.

• The total price must be shown
• The template must show unit price and total price of each item
• The order button must be connected to the set_order view

The set_order view must then redirect the user to the order_list (orders index).

[Ramin-RX7]

completed in #98