Add Setting Index_granularity_bytes (adaptive Index Granularity) for Mergetree* Tables Family

Why it matters

The new index_granularity_bytes setting allows the index granularity to be automatically adjusted based on the size in bytes, rather than a fixed number of rows. This optimizes data skipping efficiency and storage, improving query performance and resource usage for MergeTree tables.

How to use it

To enable adaptive index granularity, set the index_granularity_bytes parameter in the table creation or configuration settings for MergeTree family tables. This adjusts the index granularity dynamically based on data size, replacing the static index_granularity setting.