WEB: Deployment of the new website in production
Until now, we've been deploying the website manually afaik, from the separate repo.

What I would do with the new website is next (open to discussion):
- Have a job running to automatically deploy the website from master, possible frequencies:
  - Every commit
  - Daily
  - Weekly
- Build the website normally, as we do in https://github.com/pandas-dev/pandas/blob/master/azure-pipelines.yml#L122
- Deploy it to the server with rsync, something like: `rsync avz --delete  --exclude="docs" ~/web/build pandas_ci@pandas.io:/var/www/pandas`

For the docs, I see two main options:
- Inside `docs/` have a directory per language (currently English), and inside them one per version (with a symlink `stable/ -> 0.25.1`), so the urls would be something like pandas.io/docs/en/stable or pandas.io/docs/en/0.24.0 (and redirect pandas.io/docs/ to pandas.io/docs/en/stable)
- Copy the docs directly in pandas.io/docs/ and keep the old version in directories there pandas.io/docs/0.24.0/

In both cases, we can deploy the master docs into a `dev/` directory together with the versions.

I think the first option is a bit simpler to maintain, and the second makes the url a bit simpler. I don't have a strong preference.

I think this is very simple, but **requires that all pages that we don't want to version are in the web, and not in the docs**. So, if the roadmap is in the docs, the version we will have will be the stable version (0.25.1) and not master.

@jorisvandenbossche you proposed to have the next pages in the docs:
- Roadmap
- Ecosystem
- Contributing to pandas

Do you have a proposal for how to serve or deploy these? Or are you ok having the stable version of those? I thought about it, and I couldn't find any option I liked to keep those in the docs, that's why I'm proposing to move them to the website.