Store resolved task field values into its dynamic data

Tasks now have task data, which return serializable values.

It would be a straightforward step to serialize the resolved values in the dynamic data, so that:

• on the worker side the input fields could automatically get populated, and be available for use
• it would be possible to inspect, by looking at dynamic data in the UI, how input fields got looked up in tasks

There is some overlap with task.models.InputArtifact* introduced by Carles, which could be taken into account in design.