[Feature]: Use Polars (instead of Pandas)

### What feature do you want?

[Polars](https://pola.rs/) is an alternative to Pandas, which has an almost identical API.

A few of its benefits are listed on its homepage.
I have seen up to 3x performance gain using it in certain other applications.

We should be able to benefit from it, even if it is not adopted by pyDarshan.