Add a separate ExecutionContext for PartService and spit out more detailed logs

- During testing, I found that the execution context that runs the `time` and `timeAndTransform` methods could be bottlenecks; this fixes that.
- `PartsService` logging is more detailed now.
This should be doing the exact same thing as before, except we name the new ActorSystem that gets created if there is no application. I don't believe naming the ActorSystem has anything to do with finding the config or not.