Potential SRI Testing web service API enhancements

[RichardBruskiewich]

• [x] Finalize and deploy emerging (enhanced) reasoner-validator validation output, i.e. codified messages for 'information', 'warning' and 'error' messages, but refined response metadata.
• [ ] Add ('admin') user authentication/authorization security to the API, mainly for the /test_runs endpoint
• [x] Add an (auth/auth secured?) endpoint to cancel a running test run.
• [x] Add an (auth/auth secured?) endpoint to delete an completed test_run (from the active TestReportDatabase)

[RichardBruskiewich]

The /delete web service (and associated programmatic handler provides for gracefully cancelling an active and deleting an existing test run. This is not, however, yet secured behind auth/auth