Make teardown faster

For experiments with a large number of different Deployments and StatefulSets, the teardown takes a long time (e.g. 10-15min). This is due to the fact that Theodolite deletes a Deployment and waits until all associated pods are deleted before sending the kill command to the other resources.

With this MR, we want to send the kill command to all resources first and then wait until all associated pods are deleted.