Add pyarrow_additional_kwargs to athena.to_iceberg

**Is your idea related to a problem? Please describe.**
I need to be able to give `{"coerce_timestamps": "us"}` when writing DataFrames when writing Iceberg tables.

**Describe the solution you'd like**
Add a parameter `pyarrow_additional_kwargs: dict[str, Any] | None` to `awswrangler.athena.to_iceberg`.
