Allow nav bar to consume touch events based on configuration

This is particularly useful for OEMs that want to ensure that OEMs can
override the touch behavior of the system bars without impacting the
notification panel touch behavior.

Bug: 150613278
Test: manual, atest CarNavigationBarViewTest
Change-Id: Icb5ae3388f4004b4f465e9a9e85e8d175bbe7d78