Add generic 🤗 HF miner

[p-ferreira]

The zephyr miner is quite dynamic already, I believe that with a bit of effort, we can transform it into a generic HF miner, which would facilitate the experiments and mining experience a lot.

The model id and extra model params could be passed as parameters to the miner, which will ingest into the hf pipeline that is implemented

[steffencruz]

Closed in #91