Allow setting default_compression_codec

Why it matters

This feature addresses the problem of not having a consistent compression codec applied to MergeTree table columns when none is specified during table creation. It provides users with a way to define a default compression codec that will be automatically applied, improving compression consistency and potentially optimizing storage efficiency without needing to specify codec for each column manually.

How to use it

To use this feature, set the default_compression_codec parameter in the MergeTree table definition. When creating a MergeTree table without explicitly defining compression codecs for columns, the configured default codec will be applied automatically.