Move checkout controller + view out of order folder and into 'checkout' folder

This change will also make it so that the user is rerouted to /orders/:number upon completion of their order.
Navigate to /orders/:number once checkout has been complete
Render correct view in checkoutController
Namespace deliveryView correctly
Redirect back to products when an orders request fails
Update dependencies
Add missing translation for 'please select a shipping rate'
Add spree_gateway as a dependency
Clear localStorage order variables when order is complete
Correct please select_a_shipping_rate translation
Walkthrough cart all the way to complete