Materialized view support for Cassandra adapter

I managed to get support for a subset of Cassandra materialized views. ( Thanks owed to some hints from maryannxue!)

The one thing I noticed so far which is not supported is UUID literals in the WHERE clauses in the Cassandra view definition. However, I don't think that's a common use case. The adapter will log a warning if it encounters a view that can't be processed. At the very least, the view will be exposed as a table to Calcite (it wasn't in the previous version of the adapter).

As per CALCITE-1101, there is probably a better way to hook in and add these views. I thought I would still put this up for now. I'd still like to add some tests before considering this viable.