Support Polars Dataframe and LazyFrames

Given the meteoric rise of `Polars` in the past 2 years as a faster alternative to `Pandas`, may I suggest adding support for Polars DataFrames and if possible even Polars LazyFrames.

A new method `from_polars()` would be the ideal API imho. It should accept either `pl.DataFrame` or `pl.LazyFrame` (which needs to call `.collect()` to materialise the data for the solver)