Teach PackageManagerService about supplemental process

Each app will have it's own supplemental process with a different uid
that uniquely maps to the uid of the application that this supplemental
process corresponds to.

This will impact some of the PackageManager and PermissionManager APIs
(e.g. PackageManager.getPackagesForUid, or
PermissionManager.checkPermission). In order to make it possible for
PackageManager to correctly treat supplemental process uids, we first
need to teach it about the supplemental process APK itself, hence this
change.

Bug: 215241564
Test: atest PackageManagerShellCommandTest
Change-Id: I28f4a382900f276170c51e8c92d8fcde8419ddb1