Adding parameter-based ability to resolve expressions via management API and CLI commands

https://issues.jboss.org/browse/WFLY-1069
This shouldn't be here. The type of the reply is unconstrained; it all depends on what the attribute is.

The setReplyType(ModelType.OBJECT) here and in DEFINITION isn't really right either, but there's no real way to really declare the structure of the reply to read-attribute.