[Feature]: Migrate to only use pytest

[mavaylon1]

What would you like to see added to PyNWB?

Pynwb still uses test.py. We should migrate to pytest (as in HDMF and HDMF-Zarr).

Is your feature request related to a problem?

No response

What solution would you like?

Above

Do you have any interest in helping implement the feature?

Yes.

Code of Conduct

• [X] I agree to follow this project's Code of Conduct
• [X] Have you checked the Contributing document?
• [X] Have you ensured this change was not already requested?

[mavaylon1]

Note: I will tackle this in February 2024