Add a structured output format for actions

Currently the ospo-actions each make human readable reports, but it'd be beneficial to enable structured output like JSON which could get POSTed to a url. Users who are using an external system for logging or auditing could then parse the result and make use of the data for alerts, visualizations, etc.

Start by reading how the ospo-actions currently assemble human-readable reports and how action inputs and outputs are handled. Define the structured JSON data and POST behavior, then verify that external logging or auditing systems can parse the result and use it for alerts or visualizations.

Written by the indexing model from the issue text.