Development: find a good pattern for local doctools examples

[humitos]

Currently, we have pre-built examples for different doctools that you can access from the index page on the development server:

• Sphinx
• Pelican
• Material for MkDocs

It would be good to expand this to a pattern with the following highlights:

• Keep the sources next to the built output
• Allows us to easily re-build the docs after changing a setting
• Add more examples easily
• Don't load the repository with a lot garbage data (e.g. Docusaurus generates a lot of files)

Questions:

• How we can achieve this?
• Is it a good idea to integrate this repository with test-builds somehow?
• Can we build them on-the-fly when running npm run dev:examples? ¹

Reference: #200 (comment)

Footnotes

1. I think this will be awesome of possible! 💯 ↩