Add orderType to commerce

[grahamcrackers]

What are the schemas that are affected by the issue

https://github.com/adobe/xdm/blob/master/components/datatypes/data/order.schema.json

What are examples of products that are impacted by the issue

An order can be made at multiple points in the shopping journey. A traditional checkout is one option. Another option is 'one click checkout' or 'instant purchase' which allows customer to utilize saved billing and payment information to streamline the checkout process.