Create a skeleton Rust VHAL.

This is to prove that rust VHAL can be built and can run. The
skeleton Rust VHAL will return UNKNOWN_ERROR for all APIs.

Test: m android.hardware.automotive.vehicle-V3-rust-service
Manually replace VHAL on emulator with Selinux policy manually
updated to allow rust VHAL.
Bug: 320320087

Change-Id: I7d2dab392bf2ef982001df10c9b602c5c75888f7