Automatically upgrade the consistency level for write queries when connected to Astra

[mpenick]

Astra implements guardrails that don't allow writes at the following consistency levels (CL): ANY, ONE, LOCAL_ONE. For DataStax drivers when using the secure connect bundle the minimum CL is set to LOCAL_QUORUM. Perhaps the driver could automatically upgrade unsupported consistencies for write queries to LOCAL_QUORUM to match this behavior.