Bahrain IBAN parsing rules

Examples

    iex>  %IbanEx.Iban{
    ...>    country_code: "BH",
    ...>    check_digits: "67",
    ...>    bank_code: "BMAG",
    ...>    branch_code: nil,
    ...>    national_check: nil,
    ...>    account_number: "00001299123456"
    ...>  }
    ...>  |> IbanEx.Country.BH.to_string()
    "BH 67 BMAG 00001299123456"