Automatically add dependencies for when rules

[sebasmannem]

Steps can have one or more when rules that check if this step should be run depending on outcome of other steps.
The outcome of the other steps can only be verified if the other steps have completed, so a dependency should exist as well.
But we currently don't automatically add steps that are referenced in when rules as dependencies, they need to be added manually.

This could bring unexpected behavior where when rules (like Rc=0) check succesful while the step is still running and might end up unsuccesful later on.

We should build a list of steps being referenced from when rules, and verify if they are added as dependency.
If they are not we should issue a warning and automatically add them.