Publish versioned docs to docs.nvidia.com with a version switcher

[jayavenkatesh19]

Addition to #722

This PR is intended to move publishing docs away from stable/nightly versioning and onto the latest/YY.MM versioning scheme.

• Pushes to main publish to datascience/deployment/latest
• vYY.MM.PP tags publish to datascience/deployment/YY.MM (alpha tags do not publish)
• A version.json is published next to those directories which enables the navbar version switcher.

Both uploads go through the publish-docs and publish-one-doc shared actions. The workflow itself has no logic in it, the Sphinx build writes a small ephemeral manifest at build/publish/publish.env which specifies where the files have to be published to which is picked up by the workflow.

The version.json is created from a new Sphinx extension called rapids_docs_publishing. It runs only when the workflow sets RAPIDS_DOCS_PUBLISH=true, so local and ReadTheDocs builds do have show any switcher on the builds.

This PR also stops publishing to the old rapidsai-docs bucket and we will setup redirects on rapidsai/docs to redirect all links from docs.rapids.ai/deployment/* to docs.nvidia.com/datascience/deployment/*

Can only be merged after rapidsai/shared-actions#142 is merged. [EDIT: This has been merged]

[ncclementi]

Just checking did we end up pushing to the rapids S3? are we ready to stop publishing the rapids docs?

[bdice]

As soon as we get something on docs.nvidia.com we can stop publishing to docs.rapids.ai and add redirects.

[ncclementi]

Just to check, in the current read the docs generated in CI we do have in the nav bar the dev tag. I'm not sure if we want to keep that or if we don't care.

[bdice]

Approving with very light review since this has to be merged to be tested.

[jayavenkatesh19]

Answering @ncclementi's question, we will now not have a switcher on local/ReadTheDocs builds.

We previously had a switcher which was defined in a HTML file (see the older approach in PR changes), but the new NVIDIA theme has the option to enable the switcher only when a versions.json file is present in the build directory. We create that file in the new Sphinx extension added by the PR, and push it to the S3 bucket so that the docs.nvidia.com site does have the switcher.

[ncclementi]

Let's merge this and see what happens, as we'll need to iterate