Link from Quick Settings to Enterprise Privacy page

This CL updates the information shown in Quick Settings when a device
is managed by a Device Owner and adds a "learn more" link that takes
the user to the Enterprise Privacy page in Settings.

Bug: 32692748
Bug: 25779452
Test: runtest --path frameworks/base/packages/SystemUI/tests &
      runtest --path frameworks/base/core/tests/coretests

Change-Id: I8cbb6f2bb5c6da29ae581b6dcf7a01b1a4f2af2b