Use MODE_ASK as the default ops mode in Privacy Guard

 * Prompting the user is far more useful as a default behavior. The
   choice will be remembered after the first request.

Change-Id: Ie62f932047f8b761bd0dd9f836bcd1132062edf5
Relocate and cleanup new app ops features and PGify it

Change-Id: I4eb65f6f88c2f2aecdf054ffd52c31c4d5866900