Add select_sequential_consistency by default for CH Cloud

[koletzilla]

As described in our documentation (https://clickhouse.com/docs/integrations/dbt/features-and-configurations#read-after-write-consistency), select_sequential_consistency=1 is required to ensure read-after-write consistency.

This setting appears necessary for most dbt use cases, and we've already recommended it multiple times. Therefore, enabling it by default seems to be the right approach.However, since it impacts performance on ClickHouse open-source clusters, we should initially enable it by default only for ClickHouse Cloud clusters.

We should probably just add it similarly as we do for replicated databases https://github.com/ClickHouse/dbt-clickhouse/blob/main/dbt/adapters/clickhouse/dbclient.py#L80 by just detecting where the database is Shared

[koletzilla]

Apart from this, we should add Mutations_sync=3 and alter_sync=3 to avoid waiting for inactive replicas