Is your feature request related to a problem or challenge? Please describe what you are trying to do.

The main datafusion documentation site at https://arrow.apache.org/datafusion is good because:

1. They look good and follow the best practice for open source project documentation
2. They are associated clearly with the overall arrow.apache.org

The documentation source is at https://github.com/apache/arrow-datafusion/tree/main/docs.

https://arrow.apache.org/datafusion is updated (typically by @andygrove) when new releases of arrow-datafusion are published to crates.io (for example, apache/arrow-site#313)

However, the current setup has a few notable issues:

1. It is behind what is in the repo as it is only updated every release (every 2 weeks at the time of writing)
2. The content of the landing page in the repo (README): https://github.com/apache/arrow-datafusion has diverged from the user guide (as I believe developers want the latest content and the only way to see that without building the docs locally is README.md)
3. The manual update process is somewhat cumbersome

I think if the user guide was more immediately updated, people would be more likely to contribute to it as well.

Describe the solution you'd like
I would like some mechanism to see the latest, rendered version of the user guide as a webpage.

• On every commit to main, the site would be updated with the latest version of the user guide
• The main README.md page in arrow-datafusion would redirect to the hosted site

Bonus points for

Describe alternatives you've considered
Perhaps we could make a github pages site https://pages.github.com/ ?

Additional context