Provide schemas for json ouput intended for consumption by other tools

[hwine]

Right now, I believe this is only the output of service_report_generator.py

It would be nice to have a well documented schema, both for ensuring frost doesn't stray from it, and that consumers can understand the mapping in terms and concepts between the frost test and the report results.

[hwine]

I might cobble something together as part of generating GitHub issues from the GitHub service tests.

wip at https://github.com/hwine/frost/blob/hwine/process_report/frost/service_report_schema.yaml