Initialise global message

- Create new class to manager global message. My idea is that this class permit to manage audio or text message.
 - Update html to have main content id and inject html in this.
 - Create front event to receive startMessage and stopMessage.
 - Delete impoted variable not used.

front/src/WebRtc/SimplePeer.ts

@@ -10,10 +10,8 @@ import {
     StopScreenSharingCallback,
     UpdatedLocalStreamCallback
 } from "./MediaManager";
-import * as SimplePeerNamespace from "simple-peer";
 import {ScreenSharingPeer} from "./ScreenSharingPeer";
 import {VideoPeer} from "./VideoPeer";
-const Peer: SimplePeerNamespace.SimplePeer = require('simple-peer');
 
 export interface UserSimplePeerInterface{
     userId: string;