CreateForkNetworkMembershipsRange background migration causing massive increase in load/CPU of the primary

Running the background migration CreateForkNetworkMembershipsRange appears to increase load/CPU usage of the primary database dramatically:

This particular spike is probably the result of the jobs being scheduled/executed at once as we previously paused the queue due to similar problems being caused by background migrations (perhaps this one was too blame as well back then).

We need to find out why this migration has such an impact and reduce it, then reschedule jobs (perhaps with a larger interval).

cc @reprazent