HuggingFace model/tokenizer loader

[zyaoj]

Is your feature request related to a problem? Please describe:

Some users might want to load model ckpt directly from HF to quickly explore and do some testing.

Describe the solution you would like:

Adding a wrapper class or a model family that create_model wrapping HF lib.

Describe the alternatives you have considered:

Simply expose a functional interface as a function but this is less ideal.

Additional Context:

For directly loading qwen models (inference) that are not implemented in fairseq2 yet.

[rsyue]

Linking a relevant issue as this is partially complete:

https://github.com/facebookresearch/fairseq2/pull/1323

#1323

[rsyue]

This is completed and has been tested with 1, 2, 8 devices.

https://github.com/facebookresearch/fairseq2/tree/rsy/hg-model-v1