Create a header library for libnativewindow

After discussion, we reached the agreement that bufferhub will use
AHardwareBuffer_Desc as the standard buffer description, therefore need
to create this header lib to expose the definition for use.

Test: build passed. Not changing behavior so no further test is needed.
Bug: 118505913
Change-Id: Id2690f96f6ee79f1312076f353c2f64934654ce4