Commands should only output something on error or in verbosity mode

[alexander-schranz]

When run a command only errors should be output when run without a verbosity mode.
Else success commands will fill log files when doing a job.

e.g.

if ($output->getVerbosity() >= OutputInterface::VERBOSITY_VERBOSE) {
    $output->writeln(sprintf('Run command "%s" with workload "%s"', $handler, $workload));
}