This task will be used to track work to develop good schema guidelines for schemas within the new Modern Event Platform system.
T201063: Modern Event Platform: Schema Repostories is used to track actual implementation work of schema registries (git repositories, CI pipelines, HTTP servers, etc.), whereas this ticket should be used to collaborate and build good schema guidelines and conventions that the schema registry CI can enforce.
We need both style guides, as well as conventions for commonly used fields. We already have some good conventions for some fields in production mediawiki/event-schemas. We also need some conventions for fields we haven't needed yet for production services.