Add a new system table database_replicas

Why it matters

This feature addresses the need for easy monitoring and management of database replicas by exposing replica-related metadata in a consolidated system table. It helps users understand the state and configuration of database replicas, improving observability and operational efficiency.

How to use it

Users can query the new system table by running a SQL statement such as:

SELECT * FROM system.database_replicas

to retrieve replica information for all databases. No additional setup is required to enable this feature as it is available by default after updating to the version containing this change.