Extend voltctl to view of all Protobuf-encoded Kafka messages

VOL-2497 added voltctl support for viewing protobuf-encoded kafka events using voltctl. 

This story encompasses viewing all protobuf-encoded kafka messages, including those messages on the kafka interadapter bus between components. It's expected that the VOL-2497 solution can be heavily leveraged and/or extended to support this use case.

In the comment section of this story there is also historical information on an earlier attempt to view events using only publicly available tools (kafkacat piped to protoc) which may be of use to anyone who needs a quick way to view messages before we officially add support to voltctl. The kafka+protoc notes should not be seen as a permanent solution as they do suffer from several issues, including the incomplete decoding of Protobuf.Any.