log4j 1.2 and its MDC does not work in Java >= 9: https://blogs.apache.org/logging/entry/moving_on_to_log4j_2
Therefore we drop 1.2 and use 2.0.
We fix the broken requestId logging in RestVerticle by using the pattern
resulting in [reqId=981376281] if reqId is defined or  otherwise.
This solution allows logging with requestId for Goldenrod using Vert.x 3.9.
For Honeysuckle we will revert it, update to Vert.x 4 and use vertx context local values and JSON log lines, see
RMB-669 for details.