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-remove-item.tsx

@@ -0,0 +1,17 @@
+import { useCallback } from 'react'
+
+type Options = {
+  includeProducts?: boolean
+}
+
+export function emptyHook(options?: Options) {
+  const useEmptyHook = async ({ id }: { id: string | number }) => {
+    return useCallback(async function () {
+      return Promise.resolve()
+    }, [])
+  }
+
+  return useEmptyHook
+}
+
+export default emptyHook