[EVAL] Add tau-bench

## Evaluation short description
Similar to BFCL in #873, tau-bench is a popular agentic benchmark that is used to measure the ability of LLMs to use tools in real world domains (e.g. booking flights). It is very popular and reported in modern releases, including those from frontier labs.

We could focus on the τ^2 variant that is more recent.

## Evaluation metadata
Provide all available
- Paper url: https://arxiv.org/abs/2406.12045
- Github url: https://github.com/sierra-research/tau-bench
- Dataset url: simulated