feat(websocket)!: Implement WebSocket connection and event handling (#82)

Co-authored-by: LQ63 <lkhermann@web.de>
Reviewed-on: #82
Co-authored-by: Janis <janis.e.20@gmx.de>
Co-committed-by: Janis <janis.e.20@gmx.de>

knockoutwhistweb/app/util/GameUtil.scala

@@ -25,5 +25,5 @@ object GameUtil {
 
     code.toString()
   }
-  
+
 }

knockoutwhistweb/app/util/WebsocketEventMapper.scala

@@ -0,0 +1,20 @@
+package util
+
+import de.knockoutwhist.utils.events.SimpleEvent
+import tools.jackson.databind.json.JsonMapper
+import tools.jackson.module.scala.ScalaModule
+
+object WebsocketEventMapper {
+
+  private val scalaModule = ScalaModule.builder()
+    .addAllBuiltinModules()
+    .supportScala3Classes(true)
+    .build()
+
+  private val mapper = JsonMapper.builder().addModule(scalaModule).build()
+
+  def toJsonString(obj: SimpleEvent): String = {
+    mapper.writeValueAsString(obj)
+  }
+
+}