[rohinsuri]

Summary

• Jira: https://do-internal.atlassian.net/browse/DOCR-2560
• Add a write-only insights object to both registry create models (POST /v2/registry and POST /v2/registries).
• logs: true opts the registry in. Omitting insights or logs, and logs: false, create the registry with logs not enabled.

Test plan

• insights references insights_opt_in.yml on registry_create.yml and multiregistry_create.yml, and is not required
• insights_opt_in.yml is writeOnly, and logs is a boolean with an example
• registry.yml, registry_base.yml, and multiregistry.yml have no insights property; the 201 responses use those models
• make lint (Spectral). CI job "Validate spec" passed: https://github.com/digitalocean/openapi/actions/runs/43408515378/job/131828755538