Add display-secrets-info target and add two new headers

[mhjacks]

1. Add display-secets-info target to run display_secrets_info playbook for debugging purposes
2. Add "Debug Tasks" header for display-secrets-info
3. Add "Testing (CI) Tasks" heading (since ci-test does not seem to be a validation task, at least not in the sense that the others are)

I'm not terribly opinionated on the target's location or the header changes, so definitely willing to change those if other people disagree or don't like that

[dminnear-rh]

LGTM!