Bug: various endpoint car name faulty

[tobiasehlert]

The status, update and more endpoints are not returning car_name correct.
The cars endpoint is returning correct, so NullString is working as expected there.

example URL:

/api/v1/cars/1/status

example JSON response:

{
    "data": {
        "car": {
            "car_id": 1,
            "car_name": {
                "String": "",
                "Valid": false
            }
        },

expected JSON response:

{
    "data": {
        "car": {
            "car_id": 1,
            "car_name":""
        },

rel #242