Add the ability to change the WildFly instances log level at runtime

[yersan]

At first glance, this feature could be targeting only log modifications, but we could discuss if we want to allow to run arbitrary any CLI script. Obviously, any change applied at runtime will disappear once the container is restarted.

[jmesnil]

After working a bit on https://github.com/jmesnil/kubectl-jboss-cli plugin, I'm not sure the Operator is the right tool to run CLI scripts against WildFly servers.

The advantage of the kubectl-jboss-cli plugin is that it fits better in Kubernetes ecosystem and works fine regardless of the way WildFLy application are deployed (JKube, Helm Charts, Operators, etc.)