Update FlightRecorder options in nuxeo.conf

Since upgrade to java 11, JFR (Java Flight Recorder) is now integrated in JDK and option like UnlockCommercialFeatures are not supported anymore.

We should update this part in nuxeo.conf to have the same functionality:

## Mission control flight recorder
#JAVA_OPTS=$JAVA_OPTS -Dcom.sun.management.jmxremote.autodiscovery=true -Dcom.sun.management.jdp.name=Nuxeo -XX:+UnlockCommercialFeatures -XX:+FlightRecorder