Use https://just-the-docs.com/ template. And setup Home page.

Need to use custom deployment workflow to be able to use docs/
as source, which is slightly inconvenient compared to other themes
but might allow more customisation later.

The benefit of deploying docs is that the main/landing page will
display automatically when clicking on docs in Github. Then navigation
is straightforward.

Sections' landing pages are now rendered in github (section/README.md)
and on website (section/index.html).

Providing the pages permalink will make links to other pages
work in both Github and website.
Note the / matters at the end of the permalinks it allows to maintain
directory structure (in presence of parent/child sections) or not,

Fix tables of content.

Links to images and test files, and old html content will break,
it is fixed in following commits.

This breaks all the links, therefore needs to be fixed in following commits.

Need to use relative link to be able to render in both github and website,
absolute link can only work in both cases if root is deployed (instead of docs/).

Convert some html to markdown for picture, downside is resizing impossible in md.

Need to use relative link to be able to render in both github and website.
Other option would be to have a dedicated src/ in each section.

More than just changing the path.
For github rendering we need to
- not refer to html files
- use relative path since absolute path changes between website and github
- permalinks ensure a similar file structure

A solution to these issues would be to deploy the root of sleef,
this would have the benefit of not needing a workflow and a Gemfile.

Improve/Fix tables.
Simplify logo (rename and get rid of old ones).

Use ``` for code and command sections.
Remove <p></p> when no alignement is needed.
Reformat links using markdown

Following stuff is left for later

- Not sure what to do about titles, github does not allow
  short labels, so we would need to change the links to long titles.
- Cannot autogen TOC because headers need to be in html to allow for custom labels

Rename most logos.