common: add defer function

defer is like fn, but it waits for n SECONDS before executing

defer(durationInSeconds, fn)

Where fn is any operation

Seconds because ms is unlikely to be useful, and you can always to 0.1s. Usually JS timeouts are in ms so this might catch people out and we need to be very clear.

The implementation is like:

const defer = (durationInSections, fn) => state => {
  return new Promise((resolve) => {
    setTimeout(() => {
      fn(state)
    }, 1000 * durationInSeconds)
  });
}

You can do this in job code today but it's a bit gnarly, and it feels like a useful pattern to support.

You can compose with each nicely:

each(
  '$.patients[*]',
  defer(5, post('/patients', $.data))
)

Start by locating the existing common fn and each implementations and their tests. Add the proposed defer(durationInSeconds, fn) operation so it composes with job state and waits in seconds, then verify the delay and composition behavior with the project's existing tests.