Added info to change CONSOLE log level via jboss-cli

It is not enough to change the log level of the ROOT or a individual
logger to change the log level on the Docker container at runtime.
Also the CONSOLE log level has to be adapted accordingly. This info
was added to the README.

server/README.md

@@ -416,6 +416,7 @@ Supported log levels are `ALL`, `DEBUG`, `ERROR`, `FATAL`, `INFO`, `OFF`, `TRACE
 
 Log level can also be changed at runtime, for example (assuming docker exec access):
 
+    ./keycloak/bin/jboss-cli.sh --connect --command='/subsystem=logging/console-handler=CONSOLE:change-log-level(level=DEBUG)'
     ./keycloak/bin/jboss-cli.sh --connect --command='/subsystem=logging/root-logger=ROOT:change-root-log-level(level=DEBUG)'
     ./keycloak/bin/jboss-cli.sh --connect --command='/subsystem=logging/logger=org.keycloak:write-attribute(name=level,value=DEBUG)'