Simplify the dependencies system

[Slokilla]

We actually have two different ways to get dependencies : pipfile and pyproject.toml.

I think that we could continue only with the pyproject.toml, simplfying dependencies management.

Let's try to do anything we usually do with pipfile with pyproject.toml, and if we succeed, let's remove pipfile from the project.

[Slokilla]

Le fonctionnement avec pyproject uniquement semble marcher parfaitement :)