Convert timestamp and timestamptz to DateTime64 in PostgreSQL table engine

Why it matters

This feature enables ClickHouse to accurately map PostgreSQL timestamp and timestamptz columns to the DateTime64 type, improving precision and consistency when querying PostgreSQL tables through the PostgreSQL table engine.

How to use it

When using the PostgreSQL table engine to query PostgreSQL tables with timestamp or timestamptz columns, these data types will now be automatically converted to ClickHouse's DateTime64 type without requiring additional configuration.