Clean up navigation bar

- Move off fragments, now we have direct ownership of
  NavBarController -> NavBar (per display) -> NavBarView
- Move the nav bar components to its own package
- Removed some unused files
- Can finally dump NavigationBarController instead of FragmentService :)
- Clean up some of the dumps to be more consistent

Bug: 163690441
Bug: 158605244
Test: atest SystemUITests
Test: Test bar in various nav modes

Change-Id: I21130899df560f6cf8b7f38d4d86edca6d8f920e