API feedback: make Installer v2 API public.

Now the API if finalized, we can make it fully public.

Bug: 181708338
Test: atest PackageManagerShellCommandTest PackageManagerShellCommandIncrementalTest IncrementalServiceTest PackageManagerServiceTest ChecksumsTest
Change-Id: I2f8ec774ee8f19a1925414337e5fe8c875a6774e
4 files changed