Allow a single socket-binding-group resource as a child of profile, such that resolution of bindings from the subsystems are limited to the s-b-g associated with the profile.

A server-group that uses such a profile cannot reference a socket-binding-group. And a server in that server-group cannot reference an s-b-g to override the one from the server-group/profile.

I'm not sure how the s-b-g resource will work. Perhaps the resource would go away under 'profile' with the bindings direct children of profile. The 'default-interface' attribute then becomes an attribute of profile. Or perhaps there will be an s-b-g resource, but with a fixed name that's the same as the profile. Currently I think the latter.

This will be necessary for resolution of config elements using the upcoming provisioning tool. The tool will not be able to do correct "feature" resolution using the complex rules we currently support.