IComposerClient wrapper for VTS tests

A wrapper helps with implementation details of IComposerClient and
improves re-usability with readback and base tests.

Changes from the original wrapper (ag/16578214):

Changed the createClient to return ScopedAStatus
as it helps more with the singleton test.
And updated getDisplays to go through all the configurations
and save it in the DisplayResources as we use
the properties like width, height, vsync later
in the test and we avoid querying to the composerClient for this.

With readback tests updated setReadbackBuffer method to use
const native_handle_t* buffer instead of const native_handle* buffer

BUG: 199413815

Test: atest VtsHalGraphicsComposer3_TargetTest
Change-Id: Ia33c9489bf15a52edcae55a91ec56666df3726c1