Adding the ability to inject websites directly inside maps

This PR adds the ability to inject a website INSIDE a map (as an iframe inside a Phaser HTML object)
The iFrame will be rendered transparently, unless you set a background-color on the body, which opens a number of cool possibilities.

Needs to be done: allowing the iframe API in those iframes.

front/style/style.scss

@@ -385,6 +385,10 @@ body {
 
 #game {
     position: relative; /* Position relative is needed for the game-overlay. */
+
+    iframe {
+        pointer-events: all;
+    }
 }
 
 .audioplayer:first-child  {