ENH: let date_format take a mapping of columns to formats

[MarcoGorelli]

Feature Type

• Adding new functionality to pandas

• Changing existing functionality in pandas

• Removing existing functionality in pandas

Problem Description

follow-up to #51019

Feature Description

date_format should accept either a single format, or a mapping from column names to formats

Alternative Solutions

Just keep as-is. But this has been requested by a few people in #51019, and would be consistent with some other IO arguments

Additional Context

No response

[Nadav-Zilberberg]

I have fixed the issue by conditionally adding the 'extDtype' field in the JSON table schema only when the type is 'any'. The changes are now ready for review.