GUI for letting users choose how mapping of inputs occurs

[mvdbeek]

In #4366 @jmchilton said:

I've always wished this were available in the tool form as an option - how should mapping occur - "use input param 1", "use input param 2", "require identifiers match", "supply a regex", etc.... Should this really be a property of the tool and not a property that is set by the user - I'd argue in most cases no?

I'd love this, so I'm opening an issue to track this.