chore: reorganize docs apps (#7228)

* reorganize docs apps

* add README

* fix directory

* add condition for old docs

www/apps/resources/references/customer/interfaces/customer.CustomerGroupUpdatableFields/page.mdx

@@ -0,0 +1,11 @@
+---
+displayed_sidebar: customerReference
+---
+
+import { TypeList } from "docs-ui"
+
+# CustomerGroupUpdatableFields
+
+The updatable fields of a customer group.
+
+<TypeList types={[{"name":"name","type":"`string`","description":"The name of the customer group.","optional":true,"defaultValue":"","expandable":false,"children":[]},{"name":"metadata","type":"`null` \\| `Record<string, unknown>`","description":"Holds custom data in key-value pairs.","optional":true,"defaultValue":"","expandable":false,"children":[]}]}  sectionTitle="CustomerGroupUpdatableFields"/>