Refactor target scheduling to separate facility.
Refactor target scheduling to separate facility.

``Target`` will be refactored down the road to support various
nuanced endpoint types.  Thusly incorporating the scheduling
behavior within it will be problematic.  To that end, the scheduling
behavior has been moved into a separate assistance type to improve
conciseness and testability.

``make format`` was also run.

bluecmd/prometheus,fabric8io/prometheus,gottwald/prometheus,justintung/prometheus,dpatel06/prometheus,Dieterbe/prometheus,Gouthamve/prometheus,tattsun/prometheus,amorken/prometheus,dmilstein/prometheus,hustbill/prometheus,mrwacky42/prometheus,mtanda/prometheus,RobertKielty/prometheus,kzittritsch/prometheus,jmcfarlane/prometheus,prometheus/prometheus,JavierZunzunegui/prometheus,AlekSi/prometheus,keegancsmith/prometheus,ton31337/prometheus,q3k/prometheus,prasincs/prometheus,jimmidyson/prometheus,mtanda/prometheus,alileza/prometheus,kzittritsch/prometheus,cit-lab/prometheus,robbiet480/prometheus,trigrass2/prometheus,fabric8io/prometheus,gottwald/prometheus,fabric8io/prometheus,iksaif/prometheus,SaltedMan/prometheus-annotated,PrFalken/prometheus,eliothedeman/prometheus,msiebuhr/prometheus,Stackdriver/stackdriver-prometheus,robbiet480/prometheus,abhishekamralkar/prometheus,cit-lab/prometheus,Dieterbe/prometheus,wrouesnel/prometheus,SaltedMan/prometheus-annotated,jbdalido/prometheus,iksaif/prometheus,brancz/prometheus,thachmai/prometheus,msiebuhr/prometheus,adamron1/prometheus,adamron1/prometheus,q3k/prometheus,smyrman/prometheus,GoogleCloudPlatform/prometheus,abhishekamralkar/prometheus,trigrass2/prometheus,fabxc/prometheus,tomwilkie/prometheus,gottwald/prometheus,alileza/prometheus,jimmidyson/prometheus,dsymonds/prometheus,gcnonato/prometheus,JavierZunzunegui/prometheus,thachmai/prometheus,tattsun/prometheus,Colstuwjx/prometheus,mrwacky42/prometheus,dsymonds/prometheus,nicr9/prometheus,alileza/prometheus,ton31337/prometheus,laushinka/prometheus,eliothedeman/prometheus,GoogleCloudPlatform/prometheus,yanghongkjxy/prometheus,adamron1/prometheus,JavierZunzunegui/prometheus,hustbill/prometheus,justintung/prometheus,wrouesnel/prometheus,prasincs/prometheus,Conorbro/prometheus,keegancsmith/prometheus,wxdublin/prometheus,thachmai/prometheus,GoogleCloudPlatform/prometheus,thachmai/prometheus,cit-lab/prometheus,rajthilakmca/prometheus,fabric8io/prometheus,jmcfarlane/prometheus,brancz/prometheus,dmilstein/prometheus,tomwilkie/prometheus,brian-brazil/prometheus,GoogleCloudPlatform/prometheus,wrouesnel/prometheus,sudhi-vm/prometheus,slok/prometheus,kangwoo/prometheus,prometheus/prometheus,dsymonds/prometheus,Stackdriver/stackdriver-prometheus,jmcfarlane/prometheus,datajet-io/prometheus,sudhi-vm/prometheus,kangwoo/prometheus,gesellix/prometheus,agaoglu/prometheus,gesellix/prometheus,mrwacky42/prometheus,cit-lab/prometheus,fabxc/prometheus,RobertKielty/prometheus,flier/prometheus,ton31337/prometheus,fabxc/prometheus,wndhydrnt/prometheus,flier/prometheus,prometheus/prometheus,SaltedMan/prometheus-annotated,brancz/prometheus,eliothedeman/prometheus,kangwoo/prometheus,Stackdriver/stackdriver-prometheus,dpatel06/prometheus,jmcfarlane/prometheus,RobertKielty/prometheus,Colstuwjx/prometheus,datajet-io/prometheus,wxdublin/prometheus,eliothedeman/prometheus,PrFalken/prometheus,trigrass2/prometheus,agaoglu/prometheus,kangwoo/prometheus,smyrman/prometheus,datajet-io/prometheus,JavierZunzunegui/prometheus,gcnonato/prometheus,laushinka/prometheus,gcnonato/prometheus,slok/prometheus,slok/prometheus,adamron1/prometheus,tattsun/prometheus,gottwald/prometheus,Gouthamve/prometheus,q3k/prometheus,bluecmd/prometheus,agaoglu/prometheus,dln/prometheus,AlekSi/prometheus,yanghongkjxy/prometheus,dsymonds/prometheus,brian-brazil/prometheus,Colstuwjx/prometheus,keegancsmith/prometheus,jbdalido/prometheus,keegancsmith/prometheus,sudhi-vm/prometheus,yanghongkjxy/prometheus,trigrass2/prometheus,Dieterbe/prometheus,wndhydrnt/prometheus,PrFalken/prometheus,slok/prometheus,abhishekamralkar/prometheus,gesellix/prometheus,dpatel06/prometheus,Gouthamve/prometheus,AlekSi/prometheus,iksaif/prometheus,prasincs/prometheus,datajet-io/prometheus,tomwilkie/prometheus,amorken/prometheus,Gouthamve/prometheus,justintung/prometheus,nicr9/prometheus,tattsun/prometheus,smyrman/prometheus,nicr9/prometheus,bluecmd/prometheus,dmilstein/prometheus,yanghongkjxy/prometheus,brancz/prometheus,prometheus/prometheus,amorken/prometheus,fabxc/prometheus,tomwilkie/prometheus,dln/prometheus,rajthilakmca/prometheus,brian-brazil/prometheus,justintung/prometheus,RobertKielty/prometheus,smyrman/prometheus,Conorbro/prometheus,sudhi-vm/prometheus,abhishekamralkar/prometheus,gesellix/prometheus,prometheus/prometheus,ton31337/prometheus,Stackdriver/stackdriver-prometheus,bluecmd/prometheus,dln/prometheus,wndhydrnt/prometheus,wrouesnel/prometheus,laushinka/prometheus,keegancsmith/prometheus,gcnonato/prometheus,PrFalken/prometheus,dalanlan/prometheus,hustbill/prometheus,Conorbro/prometheus,mtanda/prometheus,rajthilakmca/prometheus,Colstuwjx/prometheus,dln/prometheus,kzittritsch/prometheus,flier/prometheus,dalanlan/prometheus,robbiet480/prometheus,iksaif/prometheus,laushinka/prometheus,hustbill/prometheus,kzittritsch/prometheus,Conorbro/prometheus,SaltedMan/prometheus-annotated,agaoglu/prometheus,alileza/prometheus,robbiet480/prometheus,jbdalido/prometheus,dalanlan/prometheus,mtanda/prometheus,dmi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