Add Readme guide for experiment

[bhack]

It could be nice if you could fill the readme template or add a tuorial for the experiments in
https://github.com/ENSTA-U2IS-AI/torch-uncertainty/tree/main/experiments

[alafage]

Hi @bhack!

Thanks for your interest in the library and your feedback. We will update the readme in the following weeks to ease the use of our experiment scripts. In the meantime, I invite you to check our CLI Guide (at https://torch-uncertainty.github.io/cli_guide.html#experiment-folder-usage) where we provide details on launching the experiments.

If you are interested in image classification experiments you can also have a look at https://github.com/ENSTA-U2IS-AI/torch-uncertainty/tree/main/experiments/classification/cifar10
I hope it helps!