SEPolicy updates for DeviceConfig Service.

Add a DeviceConfig service in system_server to edit configuration flags.
This is intended to be a command line tool for local overrides and/or
tool for tests that adopt shell permissions.

Test: None
Bug:109919982
Bug:113101834
Change-Id: Ib7bed752849b1ed102747e3202dd7aed48d2c6d5
3 files changed