Add max_concurrent_queries_for_all_users Setting

Why it matters

This feature addresses the need to control overall system query concurrency, preventing resource exhaustion and ensuring fair resource allocation by limiting the total number of simultaneous queries running for all users collectively.

How to use it

Set the max_concurrent_queries_for_all_users parameter in the server or user profile configuration to specify the maximum allowed concurrent queries globally. This can be done in the configuration files or via query-level settings depending on your setup.