HIDL VHAL interface

The HIDL VHAL interface is defined at IVehicle.hal and provides these methods.

Method	Description
`getAllPropConfigs()` generates `(vec<VehiclePropConfig>propConfigs);` Lists the configuration of all properties supported by the VHAL. CarService uses supported properties only.
`ongetPropConfigs(vec props)` generates `(StatusCode status,vec<VehiclePropConfig> propConfigs);` Returns the configuration of selected properties.
`set(VehiclePropValue propValue)` generates `(StatusCodestatus);` Writes a value to a property. The result of the write is defined per property.
`subscribe(IVehicleCallback callback, vec options)` generates `(StatusCode status);` Starts monitoring a property value change.
`unsubscribe(IVehicleCallback callback, int32_t propId)` generates `(StatusCode status);` Stops monitoring a property value change for a previous subscribed property.

The HIDL VHAL uses these callback interfaces:

Callback	Description
`oneway`	`onPropertyEvent(vecpropValues);` Notifies vehicle property's value change. Apply only to subscribed properties.
`oneway`	`onPropertySetError(StatusCode errorCode,int32_t propId,int32_tareaId);` Returns async property set errors that can not be associated with a specific set operation.