Add MergeTree Support for DiskS3

Why it matters

This feature enables users to store MergeTree table data directly on Amazon S3-compatible object storage via DiskS3, allowing scalable, cost-effective, and durable storage options beyond local disks or traditional file systems.

How to use it

To use this feature, configure a DiskS3 storage in ClickHouse settings and create a MergeTree table specifying the S3 disk in the SETTINGS clause or table configuration. This allows the MergeTree engine to read and write data files on S3 transparently.