Migrate documentation from reStructuredText to MyST Markdown

[rgaiacs]

The documentation is mostly written in reStructuredText, see docs/source, with the exception of a single Markdown file, docs/source/contribute.md.

What is the reason for only one file to be in Markdown?

Should we convert the Markdown file into reStructuredText? Or should we migrate the documentation to MyST Markdown?

[manics]

The original docs would've been in RST. When MyST came out we switched some repos to use Markdown. In some cases it was a full migration, in others MD was used for new documentation or when an existing file was being rewritten, with other existing files being left unchanged.

I think it comes down to whether migrating all docs to MD is a good use of time, and/or whether someone's keen to do it.

[rgaiacs]

I noticed that the documentation uses the directive automodule provided by the Sphinx autodoc extension, for example

binderhub/docs/source/reference/app.rst

Line 8 in 588d021

.. automodule:: binderhub.app

This will require the use of eval-rst as answer in the MyST documentation, see https://myst-parser.readthedocs.io/en/latest/syntax/roles-and-directives.html#how-directives-parse-content.