Review and cleanup for real-time specification

[getorymckeag]

Addresses https://github.com/trolie/spec/issues/100.

Includes:

• changes for real-time ratings to true up with concepts we've discussed, consistency with forecast.
• Clean up of examples, enough to show well in OpenAPI UI. Plan to add example narrative as part of next issue.
• Minor changes, including to examples in seasonal ratings, to ensure that all examples pass linter to keep clean bill of health.
• Minor beef up of tag descriptions. Plan to add more relative to this to Concepts article as part of next story on documentation/examples.
• Updated license in OpenAPI file to CSL 1.0.