Cassandra DB support for MetaModel [METAMODEL-18]

Cassandra DB support using the datastax java driver, see: https://github.com/datastax/java-driver

Integration tests have been also added. These tests need a cassandra instance running, properties to enable the integration test for this module have been added to the example-metamodel-integrationtest.configuration.properties file.
Here we return a UUID instance, while the ColumnType will be STRING. I suggest we create a UUID ColumnType so that the value corresponds to the expected type. The same principle applies probably to other column types ... Set, Map, Inet and more.