Discover workflows automatically.
Summary: Most scripts detect the relevant workflows automatically. Some scripts, however, use a hardcoded list of workflows.
Test Plan: Ran ./bin/aphlict, ./bin/cache and ./bin/phd.
Reviewers: epriestley, #blessed_reviewers
Reviewed By: epriestley, #blessed_reviewers
Subscribers: epriestley, Korvin
Differential Revision: https://secure.phabricator.com/D9564