Only get shipping rates upon clicking "review"
Currently, the cart must determine all shipping options on every single simulation in order to:
1) Tell the cart that the Shipping screen is needed before the Review screen
2) Provide the set of dropdown options for the Shipping screen
As such, we have to wait between 4-8 seconds on every simulation for the call to Process Weaver / Fedex, etc. While we are filling up the cart, we may enter 10 items and have to wait each time an item is added to the cart. This is unnecessary.
The request is for SAP to send down a simple yes/no flag to indicate if the shipping options screen is relevant.
Then, Rails should send back a request to SAP to get the shipping options only when the user has clicked on the "Proceed to shipping" button.
This would isolate the freight rate shopping call to just the checkout step and stop doing on it on every single order simulation.
Note that this idea is somewhat related:
https://feedback.corevist.com/forums/943903/suggestions/46565935