New waitlist signup

Example payload

{
  "id": "wh_15",
  "created_at": "2025-01-01 10:00:00",
  "event": "WAITLIST_SIGNUP.CREATED",
  "resource_url": "https://api.tickettailor.com/v1/event_series/es_1000/waitlist_signups?event_id=ev_15&email=email@example.com",
  "payload": {
    "object": "waitlist_signup",
    "id": "wa_83",
    "event_id": "ev_50904",
    "email": "test@example.com",
    "notified_date": {
      "date": "2020-05-01",
      "formatted": "Fri 1 May 2020 10:30 PM",
      "iso": "2020-05-01T22:30:00+01:00",
      "time": "22:30",
      "timezone": "+01:00",
      "unix": 1588368600
    },
    "created_at": {
      "date": "2020-05-01",
      "formatted": "Fri 1 May 2020 10:30 PM",
      "iso": "2020-05-01T22:30:00+01:00",
      "time": "22:30",
      "timezone": "+01:00",
      "unix": 1588368600
    }
  }
}