Updated _Sidebar (markdown)

_Sidebar.md

@@ -1,57 +1 @@
 - [**Home**](./)
-- [**An Introduction to Mail Servers**](./Introduction)
-
----
-
-#### Configuration
-
-- Your best friend [setup.sh](./setup.sh)
-- User management
-  - [Accounts](./Configure-Accounts)
-  - [Aliases](./Configure-aliases)
-- Best practices
-  - [DKIM](./Configure-DKIM)
-  - [DMARC](./Configure-DMARC)
-  - [SPF](./Configure-SPF)
-  - [Autodiscovery](./Configure-autodiscover)
-- Security
-  - [Understanding ports](./Understanding-the-ports)
-  - [SSL/TLS](./Configure-SSL)
-  - [Fail2ban](./Configure-Fail2ban)
-- When something went wrong
-  - [Debugging](./Debugging)
-  - [FAQ](./FAQ-and-Tips)
-- [Mail delivery with POP3](./Configure-POP3)
-
----
-
-#### Advanced
-
-- [Optional configuration](./List-of-optional-config-files-&-directories)
-- Maintenance
-  - [Update & cleanup](./Update-and-cleanup)
-- Override the default config of
-  - [Dovecot](./Override-Default-Dovecot-Configuration)
-  - [Postfix](./Override-Default-Postfix-Configuration)
-- [LDAP authentication](./Configure-LDAP)
-- [Email filtering with Sieve](https://github.com/tomav/docker-mailserver/wiki/Configure-Sieve-filters)
-- [Email gathering with fetchmail](./Retrieve-emails-from-a-remote-mail-server-(using-builtin-fetchmail))
-- Email forwarding with 
-  - [Relay Hosts](./Configure-Relay-Hosts)
-  - [AWS SES](./Configure-AWS-SES)
-- [Full-text search](./Full-text-search)
-- [Kubernetes](./Using-in-Kubernetes)
-- [IPv6](./IPv6)
-
----
-
-#### Tutorials
-
-- [FAQ](./FAQ-and-Tips)
-- [Installation examples](./Installation-examples)
-
----
-
-#### Use Cases
-
-- [Forward-Only mailserver with LDAP authentication](./Forward-Only-mailserver-with-LDAP-authentication)