Create MLCommons Croissant Metadata for the Datasets created by MLCommons Inference WG

[arjunsuresh]

We have some datasets like the one for Mixtral-8x7b where the dataset is created by the respective taskforce. It'll be good to have a Croissant metadata format for these.

https://huggingface.co/spaces/MLCommons/croissant-editor?project=20250202184959940380