Update the API schema to dynamically use the /events API definition from the Reader

[arnatal]

Currently the /events API (exposed in /cnwan/events in the Adaptor) is copypasted from the Reader repo. We should try to update the Adaptor API YMAL to dynamically use the one from the CNWAN Reader repo.

[jordipv]

Swagger documentation for this feature: https://swagger.io/docs/specification/using-ref/