[Hawkular-dev] Removal of embedded Cassandra

Team, As mentioned on IRC, we should not ship an embedded Cassandra with Hawkular Services. Here are a couple of approaches we can follow to accomplish that: - Keep everything as is, but change the default value for `hawkular.backend` to `remote` instead of the current `embedded_cassandra` - Remove the embedded Cassandra entirely from Nest. This has implications on how the integration tests are executed: we'd need to ensure that each integration test suite starts an embedded Cassandra before the test is executed. Or use an approach like Metrics, which requires Cassandra to be running before the tests are started. Which approach should be the one to follow? - Juca.