Vendure provider (#223)

* Minimal list/detail views working with Vendure

* Implement useCart/useAddItem

* Implement useUpdateItem & useRemoveItem

* Implement useSearch

* Add operations codegen, tidy up

* Dummy checkout page

* Implement auth/customer hooks

* Use env var for Shop API url

* Add some documentation

* Improve error handling

* Optimize preview image size

* Fix accidental change

* Update Vendure provider to latest changes

* Vendure provider: split out gql operations, remove unused files

* Update Vendure provider readme

* Add local next.config to Vendure provider, update docs

* Update to use demo server

* Fix build errors

* Use proxy for vendure api

* Simplify instructions in Vendure readme

* Refactor Vendure checkout api handler

* Improve image quality

framework/vendure/wishlist/use-wishlist.tsx

@@ -0,0 +1,46 @@
+// TODO: replace this hook and other wishlist hooks with a handler, or remove them if
+// Shopify doesn't have a wishlist
+
+import { HookFetcher } from '@commerce/utils/types'
+import { Product } from '../schema'
+
+const defaultOpts = {}
+
+export type Wishlist = {
+  items: [
+    {
+      product_id: number
+      variant_id: number
+      id: number
+      product: Product
+    }
+  ]
+}
+
+export interface UseWishlistOptions {
+  includeProducts?: boolean
+}
+
+export interface UseWishlistInput extends UseWishlistOptions {
+  customerId?: number
+}
+
+export const fetcher: HookFetcher<Wishlist | null, UseWishlistInput> = () => {
+  return null
+}
+
+export function extendHook(
+  customFetcher: typeof fetcher,
+  // swrOptions?: SwrOptions<Wishlist | null, UseWishlistInput>
+  swrOptions?: any
+) {
+  const useWishlist = ({ includeProducts }: UseWishlistOptions = {}) => {
+    return { data: null }
+  }
+
+  useWishlist.extend = extendHook
+
+  return useWishlist
+}
+
+export default extendHook(fetcher)