Allow for Custom Table Names in Cassandra Backend

[meibenny]

Describe the feature: Allow custom table names to be specified for Cassandra.

Describe a specific use case for the feature: When I need to redefine my schema, e.g. adding a property to an already defined vertex label, I need to ensure that no other processes are accessing the database during the schema change. Additionally, I need to populate the database tables with data again (usually a 2+ hour process). This means that the database is unavailable for use for 2+ hours. If we could specify custom table names, we can pre-populate new tables with the data, and then switch over to the new table, avoiding the 2+ hour downtime.

I'd like to use the same keyspace for these "new" tables.