[workflow] Add huggingface-transformers example

[rajithkrishnegowda]

Description:
This PR introduces a new example demonstrating the integration of Huggingface Transformers into openfl.

Testing
sharing the testing link with cell outputs

https://github.com/rajithkrishnegowda/openfl/blob/develop/openfl-tutorials/experimental/workflow/huggingface_test.ipynb

[kminhta]

Thanks @rajithkrishnegowda !

It's a good tutorial, but it seems very similar to your phi-4 example from the main repo. Keep in mind that openfl-contrib is not intended to be overflow from openfl, but rather a repo to welcome community contributions (i.e. research, benchmarks, experimental features, etc.)

I very much like the idea of added functionality around HF libraries, though. I think toward that direction, it would be better to focus on either very basic and well documented functionality demonstrating integration (i.e. a tutorial series) or more nuanced features and use cases