Add new dataset MMChat
_The documentation is not available anymore as the PR was closed or merged._ Thanks ! As for https://github.com/huggingface/datasets/pull/4431 please also update the licensing section in https://huggingface.co/datasets/silver/mmchat ;)

Then if it's fine for you feel free to close this PR
Hi, I am adding a new dataset MMChat. 
It seems that all tests are passed