Add support for compiling android_library modules into AARs,
and refactor app support on top of it.
Bug: 73724997
Test: app_test.go
Change-Id: I1dfac5fffe577c6680bc4709147b2061eb7d819c
Add support for android_library_import modules that take an
aar file.
Bug: 73724997
Test: m checkbuild
Change-Id: I670b56f0a3b7501d9478a6064a04d0cb9c1bb611