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/logic/user/SessionManager.scala

@@ -6,9 +6,11 @@ import model.users.User
 
 @ImplementedBy(classOf[BaseSessionManager])
 trait SessionManager {
-  
+
   def createSession(user: User): String
+
   def getUserBySession(sessionId: String): Option[User]
+
   def invalidateSession(sessionId: String): Unit
 
 }