Add Romania vehicle registration plates

### Description

Add Romanian vehicle Registration Plate Generator
https://en.wikipedia.org/wiki/Vehicle_registration_plates_of_Romania

### LINQPad Code Example

```
 var fakeAuto = new Faker<AutoObject>("ro")
         .RuleFor(a => a.Plate, (f, _) => f.Vehicle..RoRegistrationPlate())

```

### What alternatives have you considered?

No

### Could you help with a pull-request?

Yes