Vehicle HAL reference impl Part II

Implemented:
  - IVehicle::get <-- changed signature
  - IVehicle::set
  - status_t replaced with StatusCode
  - changed error handling to handle errors on SET

Test: unit tests provided
Bug: b/31971746
Change-Id: I9ea3feab7539adf588f1278fb905c0a458fa1627
18 files changed