Montenegro IBAN parsing rules

Examples

    iex>  %IbanEx.Iban{
    ...>    country_code: "ME",
    ...>    check_digits: "25",
    ...>    bank_code: "505",
    ...>    branch_code: nil,
    ...>    national_check: "51",
    ...>    account_number: "0000123456789"
    ...>  }
    ...>  |> IbanEx.Country.ME.to_string()
    "ME 25 505 0000123456789 51"