title: Create a calendar not accessible to other app on device in CalendarProvider
body: <p>AFAIK CalendarProvider is a storage where any app can read/write/edit any calendar with READ/WRITE permissons. </p>
  
  <p>I wanna create a calendar and save event, But I don't want any app on device be able to access calendar and events created by my app.</p>
  
  <p>Is it possible with CalendarProvider? If possible, How?</p>