[Feature Request] Melting Pot Integration

[GoingMyWay]

Motivation

Melting Pot: https://github.com/deepmind/meltingpot is a great MARL evaluation tool for MARL research.

Solution

Integrate Melting Pot into Env Pool

Additional context

Melting Pot was built on top of Lab2D: https://github.com/deepmind/lab2d

Checklist

• [x] I have checked that there is no similar issue in the repo (required)

[Trinkle23897]

It uses Lua for core simulation. Seems not so easy to be directly integrated into envpool.