CE: Remove compositionengine::Layer

This was a mostly straightforward refactor that restructures the
interface between SurfaceFlinger and CompositionEngine.

1) Instead of each SurfaceFlinger Layer creating and owning a
   compositionengine::Layer, each Layer instead creates and owns a
   compositionengine::LayerFECompositionState structure. Containing this
   state structure was the only real purpose for
   compositionengine::Layer.

2) Use the compositionengine::LayerFE interface in CompositionEngine in
   place of compositionengine::Layer. This includes passing a
   std::vector for the layers when SurfaceFlinger calls into
   CompositionEngine.

3) Alters the LayerFE interface to add the ability to get the state, as
   well as changing the existing "latchCompositionState" calls taking a
   state reference as the first argument into "prepareCompositionState"
   calls that do not need it, as the target of the call owns the state.

4) Alters the SurfaceFlinger Layer implementations to match the LayerFE
   interface changes.

Test: atest libcompositionengine_test libsurfaceflinger_unittest
Test: atest CtsColorModeTestCases
Test: atest CtsDisplayTestCases
Test: atest CtsGraphicsTestCases
Test: atest CtsUiRenderingTestCases
Test: atest CtsViewTestCases
Test: atest android.media.cts.EncodeVirtualDisplayWithCompositionTest
Test: go/wm-smoke
Bug: 144117494
Change-Id: Id45df7c9cc389c8fd834ba379bc0d6360a984dac