Add Python documentation to user guide

[andygrove]

Is your feature request related to a problem or challenge? Please describe what you are trying to do.
As a user reading the user guide to understand how to use DataFusion, I would like to know how to use the Python bindings.

Describe the solution you'd like
The user guide should include a section on Python bindings and explain how to use them with DataFusion and Ballista (or explain what is and is not supported).

Describe alternatives you've considered
N/A

Additional context
N/A

[matthewmturner]

@andygrove I can take this.

Ok to use whats in arrow-datafusion/python/README.md as a start and add it to the user-guide?

[houqp]

I believe by user guide, Andy was referring to https://github.com/apache/arrow-datafusion/tree/master/docs/user-guide. @jimexist @jorgecarleitao do you have any opinion on this?

[matthewmturner]

@houqp thats what i was planning on updating. I just thought that i could use the existing python walk through from the file i linked to as a starting point. maybe i misunderstood the ask though.

[jorgecarleitao]

I would not recommend mixing Python in the Rust user guide.

Most users of Python do not care about Rust and vice-versa and each programming language usually has its own way of compiling guides tailored for the language (e.g. allow code with links to the playground in Rust).

For Python, I would recommend what fastAPI (and others) do via mkdocs.

[houqp]

@jimexist is already working on a dedicated python doc site for datafusion's python binding, perhaps we could just mention and link to that doc in the main user guide when it's ready?

[jimexist]

I think I had a copy over at arrow git repo but might not have enough time to work on that this week. if you have time please feel free to take over.

[jimexist]

my unmerged patch is at apache/arrow#10982

[andygrove]

This was done some time ago: https://arrow.apache.org/datafusion/python/index.html