Add an ability to apply lightweight deletes

Why it matters

This feature allows users to perform lightweight deletions without waiting for synchronous mutation commits, enabling more efficient and immediate data deletion within ClickHouse. It improves performance by avoiding synchronous overhead and allows mutations to be applied dynamically during query execution.

How to use it

To enable this feature, set the settings as follows:

SET lightweight_deletes_sync = 0;
SET apply_mutations_on_fly = 1;

This configuration allows lightweight deletes to be applied on the fly during query processing.