Passes Injector into PackageManagerService ctor

After migrating away from locking on the package map, we can now pass in
most of what we need to PackageManagerService via the new Injector
class. This change begins the process of passing that injector in so
that we can easily mock most dependencies in unit tests.

Fixes: 137881067
Test: atest ScanTests
Change-Id: I0b0f8cf2bf59c009f2ec98147206645c84a0becc