CDK-604: Added commands to generate logging and Flume configs

* The Flume configuration defaults to an AvroSource listening on 0.0.0.0:41415
* The Flume configuration defaults to a file channel
* The log4j configuration defaults to writing to port 41415, but requires the hostname
* The log4j configuration requires a package or class name to log to Flume, or a
  switch of --log-all to configure the rootLogger.
* Besides the unit tests, I ran some manual tests on a cluster by completing the
  logging example, but using the tool derived configs rather than the ones that
  shipped with the example.
Regarding naming, "logging-config" is quite general. "log4j-config" is more indicative of what it does. We could support other logging configuration formats in the future by adding a switch, so perhaps it's OK.