Introduce s3_plain Disk Type for Write-Once-Read-Many Operations in MergeTree Table

Why it matters

This feature addresses the need for efficient storage and retrieval of data on S3-compatible storage where data is written once and read many times, improving performance and reliability. It enables users to leverage S3 storage for MergeTree tables with optimized handling, facilitating better integration with cloud object storage for scenarios where data immutability after write is expected.

How to use it

Users can configure a new disk of type s3_plain in their ClickHouse storage configuration to enable write-once-read-many access patterns. Then, they can ATTACH existing MergeTree tables located on the s3_plain disk to make use of this feature.