Add possibility to provide a priorization strategy for jobruns

[michaelschnyder]

This feature is requested from one of our projects.

They would like to prioritize manual triggered jobs higher than monthly/daily triggered jobs.
We probably don't need this information in the database itself, it might by enough when we just could give the Scheduler a hint how the plan should be ordered by an additional configuration.

Source: @samuelmeierzuehlke

[michaelschnyder]

This also relates to Jira SPPLAT-398, where an immediately run of a instant trigger is requested, See:

---

Current Situation
Excel exports join job queue behind scheduled PDF functions

New Situation
Process user's excel exports with a higher prioritization than Scheduled PDFs

Acceptance Criteria
Excel is placed at top of job queue
Scheduled PDF is still sent to the recipient with schedule assigned.

[michaelschnyder]

We could support this on different levels

1. When defining the job
2. When firing the JobRun

Or by isolating the current PriorizationLogic in a separate class that can be passed to the default Schedulers Configuration like

public class CustomPriorizationStrategy : IPriorizationStrategy
{
    public int CompareTo(JobRunAndJobAndTrigger first, JobRunAndJobAndTrigger second)
    {
        return 1;
    }
}

As discussed with @olibanjoli, we will first implement the proposed alternative to keep the flexibility for different scenarios. This implementation is also required for jobbrIO/jobbr-webapi#11

[michaelschnyder]

@samuelmeierzuehlke: Item will be moved to Version 1.1