Allow use of generic pa.DataFrameSchema/Model for different supported libraries

[DavidSlayback]

Allow use of generic pa.DataFrameSchema/Model for different supported libraries

[cosmicBboy]

I've thought about this a lot, and I think we're getting closer to this world. However my main concern is that this generic dataframe schema will have to include a superset of all the options for all of the dataframes. I think eventually we'll nail down a "common dataframe schema api to rule them all", in which case this concern is less of an issue.

We recently introduced a generic dataframe api: https://github.com/unionai-oss/pandera/tree/main/pandera/api/dataframe which is where this dispatching might happen. Currently pandas and polars schemas inherit from these classes (pyspark still needs to be done).

If folks engage with this issue (👍 or comment/discuss) we can prioritize this effort, but in the mean time @DavidSlayback if you can write down a spec for how this would all work with perhaps a code snippet sketch of how dispatching would work that would get the ball rolling.

[DavidSlayback]

Sure, I'll try to sketch something up later this week when I'm free!