refactor!: Rename structs in Rust to rename classes in R

[etiennebacher]

Close #149

I just renamed the LazyFrame class (on R side) and struct (on rust side) to RPolarsLazyFrame. This compiles and works fine. We don't need to change the docs since this is only an internal (breaking) change.

@sorhawell @eitsupi if you agree with this then I can move forward and rename DataFrame and Expr

[sorhawell]

This looks very good! I would see it as minor change as some user may have written using class() or inherits() and there have to adjust the class name.

Funny thing @paleolimbot suggested this change very early in the project history, and I was like no that would be terrible. I finally came around to like it :)

If you like you can also split it into a couple of PRs.

I looked to as if the checks were passing. I they are not and this is a draft.

[etiennebacher]

I would see it as minor change as some user may have written using class() or inherits() and there have to adjust the class name.

Yes I'll put this in the NEWS

If you like you can also split it into a couple of PRs.

I think I'll do all at once here

[eitsupi]

Thanks for working at this!
I'm definitely in favor of making all class name changes.

[etiennebacher]

I'm wondering if I should add the RPolars prefix to the other classes too, like LazyGroupBy or DataType:

https://github.com/pola-rs/r-polars/pull/554/files#diff-afa4237c90018088718e50ed6bf29c5d33bcf94ba925a9a5089683ba258e1343R270-R272

What do you think?

[eitsupi]

I'm wondering if I should add the RPolars prefix to the other classes too

I think so.

[eitsupi]

Thanks! Awesome work!

[eitsupi]

I think we may have to merge #516 first.

[sorhawell]

I think we may have to merge #516 first.

I have updated #516 , ready for review again

[etiennebacher]

Thanks for completing this PR @eitsupi