FEAT Breaking: Adding Resiliency to Scenarios

[rlundeen2]

• Added Resiliency to Scenarios so they can resume where they have an error
• Included a retry parameter to automatically retry
• Added documentation on how resiliency works
• Updated JSON retry to retry immediately and not have an exponential backoff
• Changed the return type of AttackExecutor to a new class AttackExecutorResult and added a flag so that incomplete results can be returned, even if an exception is raised.

[ValbuenaVC]

Question about overall attack design: should AtomicAttack support one or multiple objectives? It may be simpler to flatten what we currently have since the point of the AtomicAttack is to my understanding to correspond to one attack attempt. But an AtomicAttack with several objectives, especially if they aren't closely related. may undermine the purpose of the Scenario (e.g. one AtomicAttack with 20 objectives locking or busywaiting a Scenario with 19 other AtomicAttacks, each with one objective)