[Feature] Multi-agent environments with `min-max` objective

[fedebotu]

As discussed yesterday with @alstn12088 , we could add also mTSP and mPDP, and include Equity-Transformer in the benchmark @Leaveson.

I have already made an mTSP implementation in free style here As for context and embeddings, you may find them here. Finally this notebook makes a simple training for mTSP - note that most probably you can add your knowledge and make it work better!

Extending to mPDP: I can make the environment, basically just extend mTSP to deal with coupled nodes (we already have implemented PDP here These multi-agent environments with min-max objective can be a fine addition to our collection :)

• [x] mTSP
• [x] mPDP

[fedebotu]

mPDP environment added! The Equity Transformer is work in progress as there may be some refactoring in terms of training with different agent numbers :)

[fedebotu]

mPDP environment added! The Equity Transformer is work in progress as there may be some refactoring in terms of training with different agent numbers :)