Restrictions Manager

Mechanism to register a provider for requesting an
administrator to respond to permission requests.

Request format and response format constants.

Description of manifest template for static restrictions.
Int type introduced in RestrictionEntry.

Needs more javadoc and better description of manifest templates,
including specifying the XML attributes.

Change-Id: I5a654d364e98379fc60f73db2e06bf9a8310263d