Provide and match default input and output handlers for Data Functions

WHAT: Currently a Data Function author much specify the inputs and outputs for the Data Function, and that information is included in the Data Function definition. However, when a data function is added to a DXP (whether from a .dfd file or the Library), the Application Author must manually specify all the input and output handles (i.e., which Data Tables and Document Properties are used for input, which are used for output etc.) It would be useful to allow the Data Function author to specify default input and output handlers. When a Data Function is added to a DXP file, the App Author should have the option of accepting the Default handlers, or specifying new ones. Either way, if the document properties or tables don't exist, they should be automatically created. 

WHY: This would make it much, much easier to reuse Data Functions in new DXPs, with much less manually configuration required.