[docs] sphinx multiversion

[Quandevla]

Notes

• you can now close https://github.com/Quandela/Perceval/pull/281

You can remove tags we don't want with the regex smv_tag_whitelist like

smv_tag_whitelist = r'^(?!(v0\.9\.3)|(v0\.9\.1))v\d+\.\d+\.\d+$'

To test which version sphinx is goinf to build you can do

cd docs && python -m sphinx_multiversion --dump-metadata source build/html

[Quandevla]

To test this PR you can do

cd docs
make multiversion
cd build/html
python -m http.server
# go to webpage

[Quandevla]

Note that we also can deploy the docs to github page with github actions ;)

[Quandevla]

I fix I have fixed the problem with redirection.

As explained, we can withelist versions (and kinda blacklist them)

smv_tag_whitelist = r'^(?!(v0\.9\.3)|(v0\.9\.1))v\d+\.\d+\.\d+$'

Concerning the size, I think 50% of the generated docs are doctree files which are not useful for HTML (if I'm correct)

I also think that if you want to build the docs locally, we can use the make html

The make multiversion would be used only for automatic docs deployement with pipelines