add binder badge

@fekete @caillou I've added .binder directory and binder badge in README.rst.

By clicking the binder badge, users will be able to run the examples on mybinder without installing anything. Mybinder opens a Jupyter Lab interface. You should click the directory icon on the left to see the example notebooks directory. It also allows to download the generated files.

Could you please check and let me know if that would interest you? If yes, before merging I need to set badge link with the main repo ref.

Besides, I can create a docker container that would also enable users to try CLI commands, or run notebooks inside the container on their local.

How does it sound to you?