Allow PackageManager to create a new service

A new API [getNamesForUids] was recently added to the PackageManager
and this API needs to be accessible to native code. However, there
were two constraints:
1) Instead of hand-rolling the binder, we wanted to auto generate
the bindings directly from the AIDL compiler.
2) We didn't want to expose/annotate all 180+ PackageManager APIs
when only a single API is needed.
So, we chose to create a parallel API that can be used explicitly
for native bindings without exposing the entirety of the
PackageManager.

Bug: 62805090
Test: Manual
Test: Create a native application that calls into the new service
Test: See the call works and data and returned
Change-Id: I0d469854eeddfa1a4fd04b5c53b7a71ba3ab1f41