Re-introduce scaffolding functionality lost in Grails 3

originally filed here: https://github.com/grails/grails-core/issues/9854

@donald-jackson

> This is a feature request, essentially to try and get the scaffolding back to where it was in Grails 2.
>
> Two missing features are:
>
> Scripting is no longer supported in scaffolding templates (eg: iterating through a domain class to produce a view, conditions, etc)
> Scaffolding can only use domain classes from the current project, in Grails 2 you could use any hibernate class. This is useful for some people (like me) who logically separate their GUI from their domain classes.
> Thanks

The payload names no files, tests, or entry points. Read the linked original issue and compare Grails 2 behavior with the Grails 3 scaffolding templates; done means restoring template scripting and allowing scaffolding to use Hibernate classes outside the current project.

Written by the indexing model from the issue text.