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/cart/use-cart.tsx

@@ -0,0 +1,33 @@
+import type { GetCartHook } from '@commerce/types/cart'
+
+import { useMemo } from 'react'
+import { SWRHook } from '@commerce/utils/types'
+import useCart, { UseCart } from '@commerce/cart/use-cart'
+
+export default useCart as UseCart<typeof handler>
+
+export const handler: SWRHook<GetCartHook> = {
+  fetchOptions: {
+    url: '/api/cart',
+    method: 'GET',
+  },
+  useHook: ({ useData }) =>
+    function useHook(input) {
+      const response = useData({
+        swrOptions: { revalidateOnFocus: false, ...input?.swrOptions },
+      })
+
+      return useMemo(
+        () =>
+          Object.create(response, {
+            isEmpty: {
+              get() {
+                return (response.data?.lineItems?.length ?? 0) <= 0
+              },
+              enumerable: true,
+            },
+          }),
+        [response]
+      )
+    },
+}