* initial prototype for ExtendRestApi
* return before assign
* fix phplint errors
* declare Throwable
* remove empty init
* return initial data if shape is not correct
* Add IDENTIFIER to schema classes
* refactor ExtendRestApi to not use filters
* remove extra check
* implement ExtendRestAPI injected into StoreAPI schemas
* use $extend instead of $extend_schema
* fix phpcs issues
* update schema
* fix data type
* address review
* fix object cast
Co-authored-by: Darren Ethier <darren@roughsmootheng.in>
* 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
Seghir Nadir
Claudio Sanches
Darren Ethier
Mike Jolley