Adding the ability to specify a custom Jitsi URL directly in the map

This feature allows to add a "jitsiUrl" property in the map.
As a result, you can use for a given Jitsi room a custom instance of Jitsi.
Using "jitsiUrl" will only work with public Jitsi instances (authentication is not supported when "jitsiUrl" property is provided)

The Jitsi external_api.js script is now lazily loaded.

front/src/index.ts

@@ -15,13 +15,6 @@ import {MenuScene} from "./Phaser/Menu/MenuScene";
 import {localUserStore} from "./Connexion/LocalUserStore";
 import {ErrorScene} from "./Phaser/Reconnecting/ErrorScene";
 
-// Load Jitsi if the environment variable is set.
-if (JITSI_URL) {
-    const jitsiScript = document.createElement('script');
-    jitsiScript.src = 'https://' + JITSI_URL + '/external_api.js';
-    document.head.appendChild(jitsiScript);
-}
-
 const {width, height} = coWebsiteManager.getGameSize();
 
 const valueGameQuality = localUserStore.getGameQualityValue();