Documentation: Use Markdown instead of reStructuredText

[amotl]

About

@matkuliak converted significant portions of the README of influxio into MyST Markdown. However, the right spot to add this to, is here.

References

• Document InfluxDB I/O procedures crate/cratedb-guide#75

[amotl]

We have two options:

• Converge the content back into the repository's main README.md. Then, it would need to be converted into plain Markdown, and all MyST markup would get lost.

• Start establishing a real documentation on this project, and add the MyST Markdown to doc/index.md.

I am preferring to use the chance to choose the second option. Can you make that happen by submitting a corresponding patch here, @matkuliak?

[amotl]

Documentation is there now, at https://influxio.readthedocs.io/. However, not all files have been converted to Markdown, yet.

[matkuliak]

Hello. Happy to see Furo used here 🙂
Of course, I can pick this up and convert anything that's still needed into MyST Markdown.