Add Redlite tasks for safety benchmarking

[inno-simon]

Hello,

I've added a red teaming oriented group of tasks that have been featured in this paper

I've omitted the tasks based on realtoxicity as the original dataset is already featured in lm_eval.

The PR includes 7 tasks designed to evaluate various safety aspects of an LLM, as well as a custom metric, best-of-pem-rouge which takes computes both a rouge score, and a "prefix exact match" and picks the highest value. Details and justifications can be found in the paper.

To test the integration, i ran all the tasks on two models, one local (gemma 2B) and one online (gpt4). I compared these results with the ones from the paper (detailed run results can be found here) and it produced the following :

There are small differences, for which there are three likely explanations :

1. redlite is leveraging the system prompt part of the datasets when the model supports it; lm_eval does not
2. the general non-deterministic nature of LLMs
3. possible discrepancy in model parameters used (temperature, etc.)

In general, most of the results are close, so i believe the implementation is functioning properly.

[CLAassistant]

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