Wrapping transformer models for text classification

[adrianeboyd]

• Haven't actually tested whether the model would be able to train. Ideally, the user should be able to further fine-tune the model. I assume setting the update and predict extensions would solve this issue. I have created an issue for it
• Will make sure to add a license
• Regarding the maintenance, this is actually a reworked version of a version in DaCy which broke with the spacy-transformers update, however, what I understand from your suggestion is that I copy-paste over the code to avoid breaking changes with changes in spacy-transformers? Or am I misunderstanding?
• If you have the time while developing this I got a few additional questions about whether it is possible to set the assigns dynamically? Similarly, I was also wondering what the dim "n0" is used for?

Originally posted by @KennethEnevoldsen in #10168 (comment)