Display range and total mileage in miles with en_GB locale set

[TheBluProject]

With locale en_GB set, Range estimate and Total mileage still displaying in kilometers

[epenet]

It shouldn't be based on locale, but should be an independent option. I'm open to PR...

You can take a look at https://github.com/hacf-fr/renault-api/blob/main/src/renault_api/cli/main.py#L150 for adding options to CLI. And you can take a look at https://github.com/hacf-fr/renault-api/blob/main/src/renault_api/cli/renault_vehicle.py#L25 for retrieving an option (I'm not sure it's necessary to prompt - probably just default back to km if it isn't set)