Improve sample configs

1) Rename sample-task.json to sample-task-boot-and-delete.json to be more
   specific; also restructure it a bit to bring it into compliance with
   sample-task-soft-reboot.json;
2) Add sample-cloud-verification.json that shows how to use verification.

Blueprint rally-docs

Change-Id: I8fa4f92c74ec49d8637cba131c9cd309028dc73a