Contributors: Updated the service for checking your schema

In order to create a new data model or to update an existing one, Check your schema before contributing it, to check the schema on the front page.

The service has been updated to check not only the attributes of the payload but also the schema metadata (schema version, license, derivedFrom, title, description) so it will be easier to complete it before submission.

The code is available at the directory utils in the data-model repository.