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/index.tsx

@@ -0,0 +1,33 @@
+import * as React from 'react'
+import { ReactNode } from 'react'
+import {
+  CommerceConfig,
+  CommerceProvider as CoreCommerceProvider,
+  useCommerce as useCoreCommerce,
+} from '@commerce'
+import { vendureProvider } from './provider'
+
+export const vendureConfig: CommerceConfig = {
+  locale: 'en-us',
+  cartCookie: 'session',
+}
+
+export type VendureConfig = Partial<CommerceConfig>
+
+export type VendureProps = {
+  children?: ReactNode
+  locale: string
+} & VendureConfig
+
+export function CommerceProvider({ children, ...config }: VendureProps) {
+  return (
+    <CoreCommerceProvider
+      provider={vendureProvider}
+      config={{ ...vendureConfig, ...config }}
+    >
+      {children}
+    </CoreCommerceProvider>
+  )
+}
+
+export const useCommerce = () => useCoreCommerce()