Add ForeignKey on ContestoScavo for MaterialeInCassa.
Add ForeignKey on ContestoScavo for MaterialeInCassa.

And align field names to standard ones, providing a few
default values. In some cases there is not a 1:1 match
between field names and the exchange format so we use the
standard name as a prefix (e.g. two separate fields need
to be combined into one).

steko/nervia,steko/nervia,steko/nervia