Cache transformers datasets

[danbraunai-apollo]

As mentioned in #316 (comment):

Caching downloaded data (and models?) in some folder on the ssd drive. Best case we can set transformers to offline mode and shave a second off of imports (nice for fast tests!)

[nix-apollo]

We had transformers in offline mode at redwood. It was reasonably nice. Every once and a while you needed to get fresh data and figure out how to set it back to online mode. This was confusing to new people.

https://huggingface.co/docs/transformers/v4.15.0/installation#caching-models