Add notice of discontinued repo

Author: juanluisbaptiste

README.md

@@ -1,3 +1,9 @@
+<p align="center">
+<b>THIS REPOSITORY IS DISCONTINUED</b>
+<br>
+BigblueButton has an <a href="https://github.com/bigbluebutton/docker">official image</a> for quite some time now, please use that one.
+</p>
+
 # Ansible BigBlueButton Installation Role
 
 Ansible role to install [_BigBlueButton_](https://www.bigbluebutton.org) web conferencing platform with SSL support out of the box using [_LetsEncrypt_](https://letsencrypt.org/).