HuggingFace Upload Feature

[april-yyt]

Description of changes:
Implement the feature of converting models from flexflow format to huggingface format and upload models to huggingface hub. Completed reconvert methods for models:

• llama
• falcon
• opt
• mpt
• starcoder

Included an example script for downloading a model from huggingface, convert it to flexflow format, reconvert the format back to the huggingface model format(mainly modifying the weights), and eventually uploading it back to huggingface.

TODO:

• Now the conversion of qkv weights for falcon models is facing some issues to fix.

Related Issues:

Linked Issues:

• Issue Huggingface Format Convert & Upload PR Issues flexflow-serve#20

Issues closed by this PR:

• Closes #

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