implement max/min_by aggregate function

[Lordworms]

Which issue does this PR close?

Closes #12252

Rationale for this change

What changes are included in this PR?

Are these changes tested?

Are there any user-facing changes?

[Lordworms]

repushed it

[Lordworms]

An unrelated ci problem

[alamb]

I wonder if this would be a good candidate to start building a new datafusion-functions-spark crate in https://github.com/datafusion-contrib? It would be really neat if we could start filling that out (I bet the Comet team would potentially be interested too -- cc @andygrove )

Let me know and I could make you a repo

[Lordworms]

I wonder if this would be a good candidate to start building a new datafusion-functions-spark crate in https://github.com/datafusion-contrib? It would be really neat if we could start filling that out (I bet the Comet team would potentially be interested too -- cc @andygrove )

Let me know and I could make you a repo

I think it would be optimal, cc me when the repo is ready. Thanks a lot!

[alamb]

Aweomse -- I made datafusion-functions-extra and added you.

See #12254 (comment) for discussion with @dmitrybugakov and @austin362667

[Lordworms]

Aweomse -- I made datafusion-functions-extra and added you.

See #12254 (comment) for discussion with @dmitrybugakov and @austin362667

Thanks, I'll add the function there.