Add support for installing extra files from a zip file when installing
a primary file, and use it to support installing android_app_set modules,
which install a primary APK and then an unknown set of additional splits
APKs.
Test: app_set_test.go
Test: install test android_app_set
Bug: 204136549
Change-Id: Ia92f7e5c427adcef3bcf59c82a2f83450905c01d
Extract and install the primary apk normally, and then unzip the rest
of them as a post install command.
Bug: 204136549
Test: app_set_test.go
Change-Id: I17437ff27f49df6bc91bdbbea6173b46c7d3ec4e