Improved Kafak Error Handling

1) In the event of an exception in the SynchronousConsumer the time
   between retries increases exponentially, with a ceiling.
2) If the number of exceptions exceeds a configurable maximum within
   a time window, the consumer transitions to a unrecoverable state.
3) If an unrecoverable error has occurred, the SynchronousConsumer can
   optionally trigger a graceful shutdown of the Jetty Server.