Use CloudEvent SDK for Kogito processes

Rigth now, kogito-events-api include a DataEvent interface which is essentially a copy of https://github.com/cloudevents/sdk-java/blob/master/api/src/main/java/io/cloudevents/CloudEvent.java.

If we use the SDK rather than propietay classes, together with recent changes performed to use any serializer/deserialize we can take benefit of plugins like https://github.com/kattlo/cloudevents-kafka-avro-serializer, which provide us Avro serialization