doc: using arrow via arrow-extendr

[JosiahParry]

It would be great if we could link to arrow-extendr in our doc site.

It would be great if we had examples of using arrow-extendr with:

• {polars} R package
• nanoarrow
• arrow
• datafusion (for example the csv reader https://josiah.rs/posts/dfusionrdr/)