:sparkles: merge dagster-polars library

[danielgafni]

Summary & Motivation

This PR merges dagster-polars, which has been maintained in a separate repo, in the main Dagster project.

We agreed on this with @PedramNavid.

How I Tested These Changes

The PR includes tests

[danielgafni]

The docs are not ready yet, will do next week

[PedramNavid]

Thanks for submitting this @danielgafni !

Few early questions:

• Could you remove the changes to unrelated docs from this commit? We prefer to keep our commits isolated and self-contained as much as possible.
• Could you remove the files that are fully commented-out?

That will help make this easier for review! Thank you

[danielgafni]

Hey, sure!

However, I'll have to disable pre-commit in this case. I mentioned these edits were added by pre-commit automatically. This happens quite often with my Dagster PRs, I think that's because pre-commit is not being enforced by CI, which results in some commits being merged to master without running it beforehand.

Another option would be running the hooks right now in master.

A better long-term solution would be to enforce pre-commit checks in CI, otherwise one can't turn them on locally.

As for the code - for now I simply copied it from my repo without noticeable changes. We can definitely do a cleanup tho (I think there is just 1 commented tests files). One more thing I wanted to propose was moving some of the nice IOManager features I have to the UPathIOManager.

[danielgafni]

ok removed pre-commit edits!

[danielgafni]

Hey @PedramNavid , I'm done with the API docs. Would you be able to take a look at them, please?

Meanwhile I'll finish the tutorial.

[danielgafni]

@PedramNavid @erinkcochran87 I believe I'm done!