Support for "Container Subject Policy Context Handler" should be in Elytron

Support should be in WildFly Elytron, the majority of the code presently lives within WildFly Core.

However to complicate it further the current implementation presently depends upon "java.security.acl.Group" - we probably should skip this step if the Group interface is not available.

We may be able to do a better multi release jar switch later but I think that will depend upon the project moving to be built with Java 17.