[fix] Simplify save_to_hub, remove git dependency, add 'token' argument

[tomaarsen]

Fixes #1777, Fixes #1760, Fixes #1925

Hello!

Pull Request overview

• Simplify save_to_hub:
  • No more git dependency, i.e. git-lfs doesn't need to work.
  • Updated to recommended upload_folder from legacy Repository + git-lfs.
• Add optional token argument. Doesn't need to be provided if huggingface-cli login has been done.
• Add mocked tests, no actual model upload
• (Softly) deprecates the "organization" argument.
• NOTE: save_to_hub now returns the URL to the uploaded model files, not the commit!
• Update dependencies:
  • transformers>=4.32.0, required for token as used in main
  • huggingface_hub>=0.15.1 as required by transformers>=4.32.0

Details

The huggingface_hub has updated its recommended workflow on how to upload files, and this PR follows the updated version.

NOTE: save_to_hub now returns the URL to the uploaded model files, not the commit! I theorize that this is not a big issue, as I don't suspect many people to use the returned URL.
E.g.

'https://huggingface.co/sentence-transformers-testing/stsb-bert-tiny-copy/tree/main/'
# instead of
'https://huggingface.co/sentence-transformers-testing/stsb-bert-tiny-copy/commit/33dd09cf19b688db045f3850f003497d957b632b'

• Tom Aarsen