Add MedImg for streaming
### Feature request

Host the MedImg dataset (similar to Imagenet but for biomedical images). 

### Motivation

There is a clear need for biomedical image foundation models and large scale biomedical datasets that are easily streamable. This would be an excellent tool for the biomedical community.

### Your contribution

MedImg can be found [here](https://www.cuilab.cn/medimg/#).