Re-introduce scaffolding functionality lost in Grails 3

[sdelamo]

originally filed here: grails/grails-core#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