Add support for Tensorflow-datasets (tfds)

[lebrice]

Tensorflow-datasets (tfds) is a very widely-used dataset source (even though we all agree that we don't like tensorflow anymore). There might be a way to add it as an optional dependency, in case it tries to install tensorflow (which we would ideally try to avoid).

Context:

• tfds is most typically used in the Jax community (centered around Google).
• It has lots of datasets, and a nice versioning scheme and pipelining syntax. It was fun to use back in 2016.
• Might still be relevant here especially if we want to encourage Jax-afficionados to start adopting this template.