title: Android: How to add custom field/action to contact detail
body: <p>I would add custom action into system contact detail of Android like Viber (see attached screenshot) and other messaging apps do. 
  When user clicks on such custom action, my app will handle. Any help?</p>
  
  <p><img src="https://i.stack.imgur.com/hoBsb.png" alt="Contact detail with Viber&#39;s action"></p>