Previously, jobs were executed in FIFO order on MongoDB, and LIFO on
Postgres, with no way to configure this behavior.
This PR makes FIFO the default on both MongoDB and Postgres and
introduces the following new options to configure the processing order
globally or on a queue-by-queue basis:
- a `processingOrder` property to the jobs config
- a `processingOrder` argument to `payload.jobs.run()` to override
what's set in the jobs config
It also adds a new `sequential` option to `payload.jobs.run()`, which
can be useful for debugging.
Adds a `shouldAutoRun` property to the `jobs` config to be able to have
fine-grained control over if jobs should be run. This is helpful in
cases where you may have many horizontally scaled compute instances, and
only one instance should be responsible for running jobs.
