[WFCORE-22] Portiong version 1.6 of the management schema to WildFly.

Also a change to the default handling within the switch blocks so that the major version can be taken into account. i.e. In the future when we add support for version 1.7 remove the need to identify every location that 1.6 was given special handling.

Note: Once merged a Final release of WildFly Core should not be released until we are sure this schema has been release in a GA EAP release.
If this central parsing code is being used by WildFly we probably should be defining an entry point into this area of parsing that we do maintain for backwards compatibility i.e. somewhere we should add a parseValue() method that performs it's own version check - relying in the versioned methods is always going to be unstable as on forward porting from EAP it makes the code much easier to understand if the base versions a method supports are known.

I think overall I would propose we add a VaultXml.java with a single method entry point that we agree to maintain for compatibility - I can look at that if you want and port the same back to EAP with my version bump.