Re-add dns_migrate management command
Re-add dns_migrate management command

...minus the bits that just duplicate what `maintain_migrate -q` does.

akeym/cyder,akeym/cyder,OSU-Net/cyder,OSU-Net/cyder,zeeman/cyder,OSU-Net/cyder,drkitty/cyder,zeeman/cyder,akeym/cyder,drkitty/cyder,zeeman/cyder,murrown/cyder,murrown/cyder,drkitty/cyder,akeym/cyder,drkitty/cyder,murrown/cyder,murrown/cyder,OSU-Net/cyder,zeeman/cyder