FORGE-1953: Add command to get and set JVM system properties

This PR is intended to implement the feature request https://issues.jboss.org/browse/FORGE-1953.

The idea is to add a new command to get/set system properties.
Maybe having 2 commands is better, since we can ensure that an action of setting a value was intended, thus making the --value parameter required., so :+1: to that:
Eg:
- system-property-get
- system-property-get --named foo
- system-property-set --named foo --value bar