[CF1 Email Security] Adding setup page

Author: Maddy-Cloudflare

src/content/docs/cloudflare-one/email-security/setup/index.mdx

@@ -3,10 +3,10 @@ title: Setup
 pcx_content_type: navigation
 sidebar:
   order: 1
-  group:
-    hideIndex: true
 ---
 
 import { DirectoryListing } from "~/components"
 
+You can set up Email Security via:
+
 <DirectoryListing />