Add more information about the triggering object in the Task Context

[thschue]

In some cases, tasks might depend on the information stored in the triggering object (Pod, Deployment). Therefore, it would make sense to pass over information about these objects to the task execution context (e.g. annotations, labels, but not sure about the whole spec).

@thisthat, @grabnerandi: Do you have more ideas on which information this should be?

[thschue]

I think this should be revised when dealing with keptn/enhancement-proposals#91.

Therefore, closing this for now.