Alternative example for array jobs with hardcoded parameters, chosen from array instead of case statement

[eglerean]

Looks good to me. I would like the teachers of this part of next week's course to be aware of this change since it will be on the course pages so explicit ping to @rkdarst and @simo-tuomisto

[rkdarst]

This is good, though part of the reason for the case example was that it would be completely obvious to someone looking at it (the goal is more to show how it works to someone that has never seen a shell script, than provide the most recommended solution). I'd rather keep the page shorter and less advanced.

But we should have more advanced and cool array examples somewhere. This would be good there (and maybe we should move another example or two from the page there, too?) An array directory here?: https://github.com/AaltoSciComp/hpc-examples/