Document how to enable CLI logging (CLI guide)

Logging of CLI is disabled by default, but there is a way to enable it by altering a ${JBOSS_HOME}/bin/jboss-cli-logging.properties file. We should document how to enable CLI logging and point user to relevant section in documentation describing more advance logging.properties file configuration.

Current logging capabilities of CLI are quite limited. I believe we should wait with publishing of the topinc until JBEAP-4904 is resolved (but we can prepare it already).

https://access.stage.redhat.com/documentation/en/red-hat-jboss-enterprise-application-platform/version-7.0/development-guide/#example_logging_properties_file contains "JBoss Log Manager Configuration Options" section. We should add a link to this section as this is where user can find information on how to configure the logging.properties file (note that this section is a subject of JBEAP-4945).

CLI logging can be enabled by

--- a/bin/jboss-cli-logging.properties
+++ b/bin/jboss-cli-logging.properties
@@ -25,13 +25,13 @@ loggers=org,javax,org.jboss.as.cli
 logger.org.level=OFF
 logger.javax.level=OFF
 # assign a lower level to enable CLI logging
-logger.org.jboss.as.cli.level=OFF
+logger.org.jboss.as.cli.level=INFO
 
 # Root logger level
 logger.level=${jboss.cli.log.level:INFO}
 # Root logger handlers
 # uncomment to enable logging to the file
-#logger.handlers=FILE
+logger.handlers=FILE

By default, CLI logs into ${JBOSS_HOME}/bin/jboss-cli.log file