Allow initializing dummy data in test_orchestrator
During writing Teuthology tests for Dashboard/Orchestrator integration, I found it will be handy if we can specify dummy data in test_orchestrator.
Currently, there are some dummy data, but that's not flexible enough for testing.
My proposal is to add two commands in test_orchestrator module:
test_orchestrator load: load dummy data from a JSON file
test_orchestrator dump: print out current dummy data