Clickhouse metrics query isn't supporting multi-nodes cluster

[sichenzhao]

https://github.com/DataDog/integrations-core/blob/b24ab848bb79718e4963c106b47173105b81ae3d/clickhouse/datadog_checks/clickhouse/queries.py#L9

Currently metrics queries are against local system tables only in Clickhouse. If customers have multi-nodes cluster, it will just reflect the metrics of one node whichever agent is connecting to. This isn't ideal. We should leverage clusterAllReplicas or remote to get all replicas info.

https://clickhouse.com/docs/en/sql-reference/table-functions/cluster https://clickhouse.com/docs/en/sql-reference/table-functions/remote

[sichenzhao]

Hi there, how do we build/test the change locally?