feat(ui): Websocket

Started implementing functionality to Websocket.

knockoutwhistweb/app/util/mapper/RequestCardEventMapper.scala

@@ -0,0 +1,15 @@
+package util.mapper
+
+import de.knockoutwhist.events.player.RequestCardEvent
+import logic.game.GameLobby
+import play.api.libs.json.{JsObject, Json}
+
+object RequestCardEventMapper extends SimpleEventMapper[RequestCardEvent]{
+  override def id: String = "RequestCardEvent"
+
+  override def toJson(event: RequestCardEvent, gameLobby: GameLobby): JsObject = {
+    Json.obj(
+      "player" -> event.player.name
+    )
+  }
+}