Make filling in Inputs/Outputs mandatory

A lot of the time processes are published without any Input/Triggers and Outputs/Targets being specified. The Promaster should be able to enforce that (e.g. through an admin setting) for at least 1 Input and at least 1 Output to be specified for a procedure before it's published.

This can either be universal (i.e. for all Process Groups) or ideally something that can be specified for each individual process group.