docs: Delta Lake + Polars integration

[MrPowers]

Description

Add a docs page for the Delta Lake + Polars integration

[MrPowers]

@ion-elgreco - would you like to grab this one?

[ion-elgreco]

@MrPowers Sure! I'll write one after I've done some upstream changes in polars wrt MERGE

[MrPowers]

@ion-elgreco - awesome, sounds great. jfyi, these integration pages are designed to be updated as interfaces evolve. So we can write one now that explains read_delta and scan_delta and then update it with the merge section later. No rush of course, just adding this detail!

[ion-elgreco]

@MrPowers makes sense, those sections I could already do, let me look at that next week :)

[MrPowers]

This was added: https://delta-io.github.io/delta-rs/integrations/delta-lake-polars/

@ion-elgreco - would you like me to keep this one open or should we close it for now?

[ion-elgreco]

@MrPowers let's close it, we can make adjustments in future once we release new features