Include output properties in what-if deployment

**Is your feature request related to a problem? Please describe.**
The what-if option predicts the outcome of a deployment, but the output properties are not visible.

**Describe the solution you'd like**
It would be nice to include output properties so it is easier to validate that the deployment will deliver the expected output.

Bonus: when what-if supports output you can also easily verify (user-defined) functions, i.e.:


No files, tests, or entry points are named. Start by locating the what-if deployment implementation and determine where output properties are represented; done means what-if results expose those properties and the behavior is tested.

Written by the indexing model from the issue text.