Added the ability to configure the log message format for kafka
Added the ability to configure the log message format for kafka

Updated the default log message format to version 0.11.0.0 as this is the minimum needed to support kafka 2.x
If needed, the message format version can be overridden with the kafka.version flag on any of the cli tools and by calling transport.SetKafkaVersion() if using as a library

cloudflare/goflow,cloudflare/goflow