FEATURE: Interval job to optionally include job duration

[JohnRoesler]

Discussed in #564

^{Originally posted by FireSmack September 10, 2023}
I have a job set to run every 5 minutes:

s := gocron.NewScheduler(time.UTC)
job, err := s.Every(5).Minutes().Do(task)
if err != nil {
    log.Fatalf("Job %v, Error: %v", job, err)
}

I do not use WaitForSchedule() or WaitForScheduleAll().

I would like my task to always run 5 minutes after the previous iteration finishes, not every 5 minutes regardless of how long the previous run took.

Example:

Let's say the first execution of my job starts at 09:00:10 and ends at 09:00:20. The next execution will start at 9:05:10. However, is it possible to have the next execution start 5 minutes after the previous one finishes, so that the next one starts at 9:05:20? And then if that one finished at 09:05:35, I would want the following one to start at 09:10:35, not at 09:10:10. Is this possible?