HuggingFace authentication

Describes how to get a HuggingFace api key to download gated models

HuggingFace is the most used open source hub for downloading LLM model weights. Certain models are gated through the HuggingFace API authorization. It is advised to have an api key before trying to spawn an Atoma node. This can be done by following the instructions in the official documentation: https://huggingface.co/docs/hub/security-tokens