Filtering for rabbit jobs

[jameshcorbett]

@behlendorf requested some sort of utility that would return a list of jobids which ran on specific rabbits over a given time.

At the moment, given that rabbits can only be used by their local compute nodes, it would suffice to filter jobs by time and hostlist, and then apply a filter to see whether those jobs have an attributes.system.dw entry in their jobspecs.

Once rabbits can be used by any compute nodes (for lustre anyway) I'm not sure how this could be done. Thoughts?

Currently jobs that use rabbits have a memo in their eventlog which lists the rabbits they're using, that could be very helpful...