Docs/export data example

[Jaapel]

Issue addressed

Fixes Example: export_catalog

Explanation

When exporting, we can change the extension and the uri. This has to be resolved in the DataSource and the Driver. The driver now returns the "written" path when writing. This can then be used in the data source's to_file, together with some logic to get a logical basename for the file.

General Checklist

• [ ] Updated tests or added new tests
• [ ] Branch is up to date with main
• [ ] Tests & pre-commit hooks pass
• [ ] Updated documentation
• [ ] Updated changelog.rst