Scope Redis event bus queues (close #22)

- A global "scope" configuration key is added, allowing any underlying
  service to isolate data and memory from other projects/envrionments
  (e.g. it can be used as a database name prefix to differentiate
  betwwen projects).
- The Redis event bus queue is now using the scope, allowing for
  independent instances to run at the same time on the same Redis host.
Change redis queue key prefix order