Provide timing to PerformableScenario in PerformableTree
Description
Currently, timing is only provided at story level in PerformableStory.
Add timing to PerformableScenario.
Also, ensure that the Scenario model object which represents the source is only serialised once in each PerformableScenario and not repeated for each execution.
Currently, timing is only provided at story level in PerformableStory.
Add timing to PerformableScenario.
Also, ensure that the Scenario model object which represents the source is only serialised once in each PerformableScenario and not repeated for each execution.