Added Full Support for Protobuf Format (input and Output, Nested Data Structures)

Why it matters

This feature allows ClickHouse users to seamlessly work with Protobuf encoded data, a widely used serialization format, improving interoperability with systems that use Protobuf. It simplifies data ingestion and export while fully supporting complex nested schemas.

How to use it

To use this feature, specify Protobuf as the format in your queries or table definitions. For example, use FORMAT Protobuf in SELECT statements for output or specify FORMAT Protobuf for input data. Nested structures in Protobuf messages are fully supported.