* Show backorder notice in the Cart block
* Don't render variation <div> if empty
* Create ProductBackorderNotification component
* Add product backorder notification to the checkout block
* Fix classname and comment
* Rename notification->badge and don't show low stock badge if backorder is shown
* Use ternary to dispaly backorder/low stock badge
* `use` is never relative - absolute is always used so backslash is not needed
* Move process_legacy_payment code to rest api class
* Move storeapi directory
* Updated namespaces and moved tests
Albert Juhé Lluveras
Mike Jolley