Added documentation for Red5 server installation

Frédéric Burlet, the guy behind the Red5 server mods for the Dokeos videoconference, has recently added a short documentation to explain the process of installing the Red5 server on a... server. I'm adding it as is here, and I already added the file inside the documentation/ folder in Dokeos 1.8.5 stable (to come within a few days).
Dokeos Red5 applications ======================== Table of contents ----------------- 1. Installation 1.1. Red5 1.2. Dokeos Red5 Application 2. Configuration 2.1. How does it work ? 2.2. Recorder 2.3. VideoConference 3.