Andorra IBAN parsing rules

Examples

    iex>  %IbanEx.Iban{
    ...>    country_code: "AD",
    ...>    check_digits: "12",
    ...>    bank_code: "0001",
    ...>    branch_code: "2030",
    ...>    national_check: nil,
    ...>    account_number: "200359100100"
    ...>  }
    ...>  |> IbanEx.Country.AD.to_string()
    "AD 12 0001 2030 200359100100"