Added notes about disabling ma1sd

docs/configuring-playbook-ma1sd.md

@@ -6,6 +6,17 @@ This server is private by default, potentially at the expense of user discoverab
 
 ma1sd is a fork of [mxisd](https://github.com/kamax-io/mxisd) which was pronounced end of life 2019-06-21.
 
+
+## Disabling ma1sd
+
+ma1sd, being an Identity Server, is not strictly needed. It is only used for 3PIDs (3rd party identifiers like E-mail and phone numbers) and some [enhanced features](https://github.com/ma1uta/ma1sd/#features).
+
+If you'd like for the playbook to not install ma1sd (or to uninstall the previously installed ma1sd), you can disable it in your configuration file (`inventory/host_vars/matrix.<your-domain>/vars.yml`):
+
+```yaml
+matrix_ma1sd_enabled: false
+```
+
 ## Matrix.org lookup forwarding
 
 To ensure maximum discovery, you can make your identity server also forward lookups to the central matrix.org Identity server (at the cost of potentially leaking all your contacts information).