Add ordercloud provider (#500)

* Add ordercloud provider

* Fix provider errors

* Make submit checkout optional

* Make submit checkout optional

* Remove nullables when creating endpoint type

* Update readme

* Log checkout error

* Log error

* Save token to cookie

* Update fetch rest

* Use token at checkout

Co-authored-by: Luis Alvarez <luis@vercel.com>

framework/ordercloud/api/endpoints/checkout/index.ts

@@ -0,0 +1,23 @@
+import type { CheckoutSchema } from '../../../types/checkout'
+import type { OrdercloudAPI } from '../..'
+
+import { GetAPISchema, createEndpoint } from '@commerce/api'
+import checkoutEndpoint from '@commerce/api/endpoints/checkout'
+
+import getCheckout from './get-checkout'
+import submitCheckout from './submit-checkout'
+
+export type CheckoutAPI = GetAPISchema<OrdercloudAPI, CheckoutSchema>
+export type CheckoutEndpoint = CheckoutAPI['endpoint']
+
+export const handlers: CheckoutEndpoint['handlers'] = {
+  getCheckout,
+  submitCheckout,
+}
+
+const checkoutApi = createEndpoint<CheckoutAPI>({
+  handler: checkoutEndpoint,
+  handlers,
+})
+
+export default checkoutApi