jobrunner: provision on mw1001; fix template

* Qualify references to instance vars with '@'
* Coerce {aggr,queue}_servers to array and join into a comma-separated list.
* Add to production mediawiki jobrunner class, but confine to mw1001 for now.

Change-Id: Iec38db6016a8d759562724c8ac932aff1b8919d2