STREAMS-243 | S3PersistWriter No Longer Dies Silently

Added more detailed logging in the S3PersistWriter's prepare method so that we can see any issues as they arise. Added tests to the S3PersistWriter to assert that appropriate exceptions are thrown when expected. Updated code in LocalStreamBuilder to ensure that the 'isRunning' calculation is more accurate.
It ensure date-time fields are written as RFC3339 strings rather than joda json documents.