feat(auth): add authentication endpoints (#6265)

**What**
- Add authentication endpoints: 
  - `/auth/[scope]/[provider]` 
  - `/auth/[scope]/[provider]/callback`
- update authenticate-middleware handler
- Add scope field to user
- Add unique constraint on scope and entity_id

note: there's still some remaining work related to jwt auth to be handled, this is mainly focussed on session auth with endpoints



Co-authored-by: Sebastian Rindom <7554214+srindom@users.noreply.github.com>

integration-tests/plugins/helpers/create-authenticated-customer.ts

@@ -13,6 +13,7 @@ export const createAuthenticatedCustomer = async (
   const authUser = await authService.createAuthUser({
     entity_id: "store_user",
     provider_id: "test",
+    scope: "store",
     app_metadata: { customer_id: customer.id },
   })