Support iceberg writes to read from pyiceberg

Why it matters

This feature enables ClickHouse to perform writes to Iceberg tables, a popular open table format for analytic datasets, by leveraging metadata read through PyIceberg. It enhances interoperability with Iceberg-managed data, providing users with seamless integration between ClickHouse and Iceberg storage layers.

How to use it

Users can enable Iceberg writes in ClickHouse by configuring tables with the Iceberg engine and ensuring PyIceberg metadata access is properly set up. Once configured, write operations targeting Iceberg tables will utilize PyIceberg to read metadata and manage data writes accordingly.