Document jul/log4j2 JVM options that might be needed

``` -Djava.util.logging.manager=org.apache.logging.log4j.jul.LogManager -Dlog4j2.julLoggerAdapter=org.apache.logging.log4j.jul.CoreLoggerAdapter ``` The latter is needed as of 2.24.0 for some libraries that rely on j.u.l.'s API to programmatically set log levels. See https://github.com/apache/logging-log4j2/issues/2353 For the former, see https://logging.apache.org/log4j/2.x/log4j-jul.html