- Bottom line - we need to manage shutting down gracefully when doing long-running tasks
- To achieve that, we're going to use job queues
In this commit:
- added new @tryghost/job-manager dependency
- added a minimal job service, that handles in passing things like logging and (maybe later) config
- job service is wired up to server shutdown, so that the queue finishes before the server exits
- also added a new job endpoint to testmode so that it's easy to test job behaviour without needing to do real work
