User authentication worker - stores/retrieves it from data source
 public SqApiServiceFacade(string apiUrl, string userName)
 {
     url = apiUrl;
     userAuthWorker = new UserAuthWorker(userName);
 }
 public SqApiServiceFacade(string url)
 {
     this.url = url;
     userAuthWorker = new UserAuthWorker();
 }