Issue 208 ofx files

[tolland]

just to create the link to the issue https://github.com/arrobalytics/django-ledger/issues/208

[elarroba]

@tolland thank you for your PR... I'll be reviewing this soon....

[tolland]

Tests succeed on the new tests:

(.venv) [django-ledger] $ python manage.py test django_ledger.tests.test_io_ofx 
Found 3 test(s).
Creating test database for alias 'default'...
System check identified no issues (0 silenced).
07/01/2024 10:52:35 AM Populating Entity Testing Inc-439127...
...
----------------------------------------------------------------------
Ran 3 tests in 8.225s

OK
Destroying test database for alias 'default'...