* add selecting rate resolution state to the cart store
* expose whether rate is being selected on useSelectShippingRate
* Cleanup and refactor ShippingDataProvider
- remove un-needed component and move shipping rates into context provider
- remove error handling (currently the ui/ux for the checkout should result in no errors and any api errors are non-recoverable).
- Add logic for shipping rate selection into context provider and add event emitters for it.
- increment/decrement checkout calculation counts when shipping rates are being selected.
* dispatch checkout error if there is an error
* disable place order button if checkout is calculating or has error
* update doc block
* fix convention for js comment blocks