Add fast checkout hydrateOrder endpoint

[nicolenorman]

Add a new class which hits the fast checkout hydrate order endpoint.

This will hydrate a Bold simple order type with data from a Magento quote.

[mwraich]

So looks good, testing on my shop though I got the following error:

{
    "status": 422,
    "errors": [
        "{\"errors\":[\"Error at '\\\/totals\\\/discount_total': Value is not nullable\"],\"message\":\"Request validation failed for the reasons noted\"}"
    ],
    "body": []
}

I didn't have a discount present.

[nicolenorman]

So looks good, testing on my shop though I got the following error:

{
    "status": 422,
    "errors": [
        "{\"errors\":[\"Error at '\\\/totals\\\/discount_total': Value is not nullable\"],\"message\":\"Request validation failed for the reasons noted\"}"
    ],
    "body": []
}

I didn't have a discount present.

Thank you for catching this @mwraich ! Just pushed a small change to account for no discounts.