Add support for Apache Cassandra DB

Install, configure and initialize Apache Cassandra v2.0 database for FrameworkBenchmarks.
@hamiltont @aschneider-techempower from Cassandra db point of view the only consideration is security, other than that user account selection is arbitrary, so e.g. "tfb" or "cass" (or anything else) could be used.

Do you have a preference? Should a TFB or database specific user account be used?