Add getPackageInfo to IPackageManagerNative

The new native OMAPI service (replacing the existing Java APK-based
implementation of OMAPI, mostly because OMAPI is needed during early
boot and the Java OMAPI cannot start early) needs to retrieve package
information from PackageManager.  It doesn't need to get the package
info during early boot, only later when Android apps begin using it.

This is not flag-protected because AIDL does not support flagging and
the implementation must be included with the AIDL method definition.

Bug: 380331467
Test: atest CtsPackageManagerTests
Flag: EXEMPT HAL interface change
Change-Id: If754dcd3ac5725eedc9469bd1793a8dab1ef7963