[RF] RooStats tutorials translated into Python

[PPaye]

This Pull request:

roostats tutorials translated into Python

Changes or fixes:

The unmarked C++ roostats tutorials have been translated into python3.

Checklist:

• [ yes ] tested changes locally with ipython3
• [ yes ] updated the docs

This PR fixes # https://github.com/root-project/root/issues/8758 and should close the issue.

[guitargeek]

Dear @PPaye, thank you for this contribution! Now that the 6.32 release has happened, we can focus on nice documentation improvements like these.

Before I can run the CI, would you mind to:

• Move all the files into the tutorials/roostats folder? We also don't have the few existing Python tutorials in roostats-py, so it would be better to stay consistent.

Once this change is done, we can do a CI run and I will do a deeper review. You should also consider rebasing your commit onto the tip of the master branch, which advanced quite a bit in the meantime.

Sorry for coming back to this so late! Jonas

[guitargeek]

Hello @PPaye! Can you please resolve the conflicts by rebasing your commit onto the current ROOT master? Otherwise we can't proceed here. Thanks!