Add intent for permission usage info learn more

The manifest permission usage info declarations are limited in what they
allow the applications to specify. Applications can have an activity for
that handles this intent in order to provide free form application
specific details such as privacy policies, specific examples, etc.

Test: API definition, usage will follow
Bug: 111207567
Change-Id: I90b292e4c1cb8847a9a9d7b8071aaff2ee7d11fb