Added /me/event + registration info per event

Added:

1. /me/event
2. /me/event?type=PAST (no thank you comments yet)
3. registrationInfo for each event

  public enum RegistrationInfo {
    ORGANIZER,
    REGISTERED,
    WAIT_LISTED,
    CAN_REGISTER,
    CAN_WAIT_LIST,
    FULL
  }

Requirements:
All events must be re-created. Changed how participants are stored in the db.