Add architecture overview diagram.
Add architecture overview diagram.

Change-Id: I860a748be534b2b9b0b60a9dd2e4436b78cc3907

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