feat(ui): Websocket

Started implementing functionality to Websocket.

knockoutwhistweb/app/util/mapper/GameStateChangeEventMapper.scala

@@ -0,0 +1,18 @@
+package util.mapper
+
+import de.knockoutwhist.events.global.GameStateChangeEvent
+import logic.game.GameLobby
+import play.api.libs.json.{JsObject, Json}
+
+object GameStateChangeEventMapper extends SimpleEventMapper[GameStateChangeEvent]{
+  override def id: String = "GameStateChangeEvent"
+
+  override def toJson(event: GameStateChangeEvent, gameLobby: GameLobby): JsObject = {
+    println("CALLED toJSON FOR GAMESTATECHANGE")
+    Json.obj(
+      "oldState" -> event.oldState.toString,
+      "newState" -> event.newState.toString,
+      "gameLobby" -> gameLobby.id
+    )
+  }
+}