[Docs tooling] Set up Hugo

[kickoke]

To simplify our docs setup, I want to set up a Hugo environment along with the tufte css template.
Pros:

• Tufte allows us to annotate our content
• Hugo is supported by the tech team
• Learning curve is less steep than with Docusaurus

CC: @bwklein

[kickoke]

Preview: https://24-hugo--docs-chronologue.netlify.app/

Still to do:

Content

• Clean up frontmatter to match with what Hugo supports
• Create navigation for the API docs and the Chronologue user guide
• Flesh out homepage

Adjust CSS:

• Rewrite CSS so that margin notes don't break.
• Add responsive design

Documentation

• Write down how the repository works and how to add/maintain content.

Publication

• Merge into docs branch
• Resolve merge conflicts

See Tufte features: https://raw.githubusercontent.com/shawnohare/hugo-tufte/master/exampleSite/content/post/tufte-features.md

[kickoke]

Disregard the above comment.

I am working on a simple theme for our docs, since the fixes began to become endless...