ENG-1455: Dual-read from old-system settings and from blockprops#812

sid597 wants to merge 10 commits intomigration-block-init-staging-branchDiscourseGraphs/discourse-graph:migration-block-init-staging-branchfrom

eng-1455-add-old-system-read-routing-to-accessor-gettersDiscourseGraphs/discourse-graph:eng-1455-add-old-system-read-routing-to-accessor-gettersCopy head branch name to clipboard