Add support for huggingface embedding models

[gabrielchua]

Is your feature request related to a problem? Please describe. A user currently cannot add their own embedding models.

Describe the solution you'd like To integrate with hugging face.

Additional context

• See embeddings.py in the experiment branch
• This seems promising: https://docs.trychroma.com/embeddings/hugging-face

[gabrielchua]

I'll be able to hack this out by this weekend, but if anyone would like to give it a shot for the experiment branch. Please ping!