[Enhancement] : Webhooks/notifications when a schema is registered/updated

We have producers `POST`ing the schemas to schema registry and consumers running off those schemas. As consumers reside in a different environment, they are not able to communicate to schema registry. In this case, we apply the following deployment setup:

- Producer publishes the schema in schema registry
- Consumer is built off that schema and deployed
- Producer produces events and consumer receives it

Although in this scenario, schema registry is not acting as an active services for both producers and consumers, we need it for maintaining the avro specification/standards and compatibility. So, we need consumers to be automatically built when a schema is registered/updated.

Ideally, it would be good to have notification channels/webhooks for this setup.

Start by mapping the schema registration and update REST flows and reviewing the producer/consumer deployment setup described in the issue. Define what notification delivery should cover for each registration or update and how completion would be verified, since the issue does not name implementation files, tests, or a specific webhook channel.

Written by the indexing model from the issue text.