Quick demo of how to use RowTypeInfo to ensure better validation of the event data within the pipeline

• use the proper RowTypeInfo at every step of the pipeline (tho require a cumbersome Tuple2 to carry the error or the event)
• route errors to a side-output
• some pom cleanups

The MR is not meant to be merged as-is but meant to be a quick demo of how to properly propagate the RowTypeInfo obtained from the wikimedia-eventutilities.