Create readthedocs/sphinx site

[sverhoeven]

The README is becoming large and mixes user and developer docs.

It would be nice to have a documentation site using Sphinx and hosted on Readthedocs.

Use https://i-vresse-bartender.readthedocs.io/ as https://bartender.readthedocs.io/ is already taken.

README could be split into

• CONTRIBUTING.md
• docs/index.md
• docs/usage.md
• docs/user_management.md
• docs/configuration.md

[Peter9192]

Or use GH actions bartender.github.io? Ben recently wrote a nice blog about versioned docs on GH pages.

[sverhoeven]

Add Markdown support with myst see https://github.com/i-VRESSE/bartender/pull/17/files#r1085534781

[Peter9192]

On myst compatibility with sphinx v6, there are two issues and a merged PR: https://github.com/executablebooks/MyST-Parser/issues/660, https://github.com/executablebooks/MyST-NB/issues/466, https://github.com/executablebooks/MyST-Parser/pull/664, just no new release yet.

[Peter9192]

To do:

• [x] move https://github.com/i-VRESSE/bartender#haddock3-example to https://github.com/i-VRESSE/bartended-haddock3 and link to that.
• [x] TLDR/quickstart will be deployment only, move detailed instructions to developer chapter.
• [x] Move advanced config example to dedicated docs page
• [x] Make TOC and landing page play nice