docs: update bulk editor user guide + add redirect from old v1 next js (#12104)

* docs: update bulk editor user guide + add redirect from old v1 next js

* update page titles

www/apps/book/app/learn/customization/integrate-systems/handle-event/page.mdx

@@ -1,7 +1,7 @@
 import { Prerequisites } from "docs-ui"
 
 export const metadata = {
-  title: `${pageNumber} Guide: Sync Brands from Medusa to CMS`,
+  title: `${pageNumber} Guide: Sync Brands from Medusa to Third-Party`,
 }
 
 # {metadata.title}