Move documentation from Advanced to Best Practises

Also suppress ToC while here.

docs/content/config/best-practices/mta-sts.md

@@ -1,5 +1,7 @@
 ---
-title: 'Advanced | MTA-STS'
+title: 'Best practices | MTA-STS'
+hide:
+  - toc # Hide Table of Contents for this page
 ---
 
 MTA-STS is an optional mechanism for a domain to signal support for STARTTLS.

docs/content/config/environment.md

@@ -115,7 +115,7 @@ Enables MTA-STS support for outbound mail.
 - **0** => Disabled
 - 1 => Enabled
 
-See [MTA-STS](advanced/mail-mta-sts.md) for further explanation.
+See [MTA-STS](best-practices/mta-sts.md) for further explanation.
 
 ##### ENABLE_OPENDKIM