Added Restoration of MergeTree Parts to Detached Directory for S3 Disk

Why it matters

This feature allows users to recover or restore data parts of MergeTree tables from backups or prior states directly into the detached directory on S3 disks. It solves the problem of limited restoration options for data stored on S3, enhancing data recovery workflows and enabling safer troubleshooting or manual data repairs without affecting the active dataset.

How to use it

When using S3 as the storage disk for MergeTree tables, users can now restore data parts by placing them into the detached directory. This directory acts as a staging area where parts can be checked and later attached to the table using standard ClickHouse commands like ALTER TABLE ... ATTACH PART.