Layout status/nav bar and decor window as normal window

Use the general layout process for system bar windows. The hard-coded
logic of the bar position is also disabled by the patch. Such that, the
system UI will have the ability to layout the window freely.

The bars sometimes need to be layout with new rotation before the actual
rotation when we simulate the display with fixed layout. To support
that, new layout params for orientation is introduced to the layout params.

The bar may need to provide a different insets frame in gesture
navigation mode. That is for the IME to draw the hide button. Introduced
a new param called providedInternalInsets to resolve that usage.

The new flexible layout is protected by the flag
persist.debug.flexible_insets.

Bug: 161689946
Bug: 169329927
Test: DisplayPolicyTests InsetsSourceProviderTest
      InsetsStateControllerTest
Change-Id: If8ec79b3cb3b989eed578c44e8749b13fd2e8592