Remove hwcomposer2.h

Previously SurfaceFlinger codebase uses hwcomposer2.h, which contains a
bunch of types that are not versioned. The usage of hwcomposer2.h has
been causing static casting here and there. This patch removes the usage
of hwcompoer2.h, creates a Hal.h to capture all composer hal stuff that
the codebase relies on.

Bug: b/77585359
Test: atest libsurfaceflinger_unittest
Test: atest SurfaceFlinger_test
Test: atest libcompositionengine_test
Change-Id: If9dfeb2a4a2c2f9df0b3ed300bfaca22c463038e