JBIDE-13938 Explicit WildFly support and versions are now derived from appropriate name of server adapter

Changes in XML Schema:
 - explicit support for WildFly.
 - versions for all families are derived from appropriate name of server adapter (that's a reason why for EAP we have version 6.1+)

Interface ServerFamily and classes implementing this interface were moved to their own package ( *.family)

Refactored ServerRequirement. Basically all the refactoring was aimed to make method fulfill() more readable and less use of exceptions.

Component: RedDeer server requirements for JBT
Author: rrabara