[DISCUSSION] Should DataFusion project use `lib.rs` pattern/antipattern?

### Is your feature request related to a problem or challenge?

There is an article I found pretty recently https://kerkour.com/rust-patterns-dont-put-code-in-lib-mod-files

Which suggests using certain file names instead `package/lib.rs` and I'm feeling it has some reasoning behind it. Even in Github when you search by file and this is often a `lib.rs` you got a pile of `lib.rs`'s

Just wondering what you guys thinking about it.

@alamb @andygrove @viirya @mustafasrepo @ozankabak @jayzhan211 @waynexia

### Describe the solution you'd like

_No response_

### Describe alternatives you've considered

_No response_

### Additional context

_No response_

Start by reading the linked article and inspecting the DataFusion repository's existing lib.rs files to understand the current module layout. The issue does not name a target file or concrete change; done would require an agreed project-wide convention and a recorded decision about whether to adopt it.

Written by the indexing model from the issue text.