DMN16 — Allow input data to be of type Interval

In many situations, it is desirable to have a data input that is an interval. Particularly when it comes to temporal logic many situations requires one to enter the "Valid Period", the "Measurement Period", the "Disccount Period" etc
To currently achieve this requires to create two data inputs (one for the start data/time and one for the end data/time) and then assembling them into an interval named "Period using a literal expression [start..end].