added nox -e clean

[DavideTisi]

added nox -e clean to clean all the temporary files in examples.

followed @ceriottm discussion this is a proposal for implementing the clean function in nox.
it uses git ls-files --other example to check all the files not git tracked in the example dir

[github-actions]

Here is the build version of the cookbook in this pull request: documentation.zip, you can view it locally by unzipping documentation.zip and open the index.html with your favorite browser.

[ceriottm]

With @Luthaf we were discussing of how we should call this target. clean-build seemed a good descriptive one. I'd also add docs/build, and .nox if you haven't added those already.

[DavideTisi]

I thought we did not want to add .nox

[ceriottm]

OK, I went through this and as far as I'm concerned, I'm happy. I separated clean_build from clean_examples, as I think people may want to keep experiments in examples sometimes, but need to clean the build. Maybe this approach gives us more flexibility to keep stuff we don't want to remove for some reason.

[DavideTisi]

for me it is fine

[DavideTisi]

@ceriottm do we want to merge this?
@Luthaf @PicoCentauri what do you think ?

[ceriottm]

Lgtm, I think I cleaned it up a while ago

[Luthaf]

comment seems duplicated

[Luthaf]

why .nox? this will remove itself when running =/

[DavideTisi]

@ceriottm I think you added that piece

[DavideTisi]

Even without michele comment I kind of agree that removing folders like .nox is the point of this function

[Luthaf]

hmm, I see this more as a way to clean temporary files created by the example, not to clean the virtualenvs. Also rm -rf .nox is trivial compared to what nox -e clean does, so leaving them separate is not too much of a burden on the end user.

[ceriottm]

So, the rationale for this whole PR is to have a setup similar to the clean_python script of other projects, wiping all build and caches. Upon checking, it's true that all of those don't wipe .tox so even though I added it in the first place, I now agree that for consistency we should not (or we should do this consistently everywhere). Removing it for now (and merging)