As cassandra start script hardcodes the location of logback
configuration to `CASSANDRA_CONF_DIR/logback.xml` there is no way to
pass an alternate file via `$JVM_OPTS` for example.
Also, without logback configuration DEBUG level is used which is not
necessary for standard usage.
With this commit a default logback configuration is set with log level
INFO.
Configuration borrowed from:
https://docs.datastax.com/en/cassandra/3.0/cassandra/configuration/configLoggingLevels.html
The module will configure a Cassandra server with common options being
tweakable. Included is also a test which will spin up 3 nodes and
verify that the cluster can be formed, broken, and repaired.