beta: lower # of procs on jobrunner

The beta cluster jobrunner spawns so many jobs that it starves the
application servers via api call.  Vary jobrunner parameters by $::realm
and lower the # of procs spawned on beta.

Bug: 63315
Change-Id: Icd33ade06d86404cdb756294590cd5a23d5db6d0
Merge "beta: lower # of procs on jobrunner" into production