adds llm as judge using transformers

[NathanHB]

• lazy load of openai and transformers lib
• able to use openai client to prompt transfrmers models
• add llama 3.1 405B as llm as a judge in default metrics
• update doc
• make sure we are not rate limited
• add option to use local transformer model as judge

[clefourrier]

LGTM, just need to

• rename the api call function
• add some docs in the README
• add some checks on the answers to make sure we are able to filter when model as a judge times out for ex

[clefourrier]

Don't forget to update the README with the new metrics