Support to prioritize the execution of parallel stages, sorted by the start-time of the parent job.

We have jobs that use multiple executors via parallel stages.
When our jenkins cluster is under heavy load, it happens often that we end up with having a lot of half-finished jobs, that wait for executors in parallel stages.

Being able to prioritize parallel stages would result in that builds started can finish before new ones are started.

To also enable that build started first can finish first, it would be great if it would also be possible to prioritize execution of parallel stages ordered by the start-time of the job that they are part of.