Protocol Changes

⚠️ This release includes breaking changes ⚠️

Changed:

1. The Job protocol is no longer constrained to Codable.
2. The Job protocol now has a Codable associatedtype
3. Added a JobData protocol
4. Renamed JobData -> JobStorage
5. Updated the JobsPersistenceLayer to pass JobStorage objects rather than strings
6. Removed Worker parameter requirement from Job protocol. EventLoops can be accessed via context.eventLoop

Upcoming:

1. Reliable queue worker: vapor run jobs --reliable will run a single worker that will move stale jobs from the processing queue back to the upcoming queue.
2. Scheduled jobs