This commit removes the implementation summary for IBAN test coverage and adds a new module to generate test fixtures in
JSON format from the IBAN examples.
- Added `iban` field to the `IbanEx.Iban` struct to hold the full IBAN value. - Updated the parsing logic to populate
the new field. - Adjusted BBAN rules and tests for France and Brazil to reflect updated structures. - Improved error
handling and format validation routines.
