docs: added customer storefront guides (#7685)

* added customer guides

* fixes to sidebar

* remove old customer registration guide

* fix build error

* generate files

* run linter

www/apps/resources/app/commerce-modules/region/page.mdx

@@ -60,7 +60,7 @@ const regions = await regionModuleService.create([
     name: "United States of America",
     currency_code: "usd",
     countries: ["us"],
-    payment_providers: ["stripe"]
+    payment_providers: ["stripe"],
   },
 ])
 ```