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/provider.ts

@@ -0,0 +1,21 @@
+import { Provider } from '@commerce'
+import { handler as useCart } from './cart/use-cart'
+import { handler as useAddItem } from './cart/use-add-item'
+import { handler as useUpdateItem } from './cart/use-update-item'
+import { handler as useRemoveItem } from './cart/use-remove-item'
+import { handler as useCustomer } from './customer/use-customer'
+import { handler as useSearch } from './product/use-search'
+import { handler as useLogin } from './auth/use-login'
+import { handler as useLogout } from './auth/use-logout'
+import { handler as useSignup } from './auth/use-signup'
+import { fetcher } from './fetcher'
+
+export const vendureProvider: Provider = {
+  locale: 'en-us',
+  cartCookie: 'session',
+  fetcher,
+  cart: { useCart, useAddItem, useUpdateItem, useRemoveItem },
+  customer: { useCustomer },
+  products: { useSearch },
+  auth: { useLogin, useLogout, useSignup },
+}