Support DataRef cloudevent extension

In the CloudEvent spec, there is the `dataref` extension defined:
https://github.com/cloudevents/spec/blob/main/cloudevents/extensions/dataref.md

It would be nice to have a way to make use of this, especially to avoid sending large data, e.g. in sources that shuffle data, like from AWS for example:

```yaml
apiVersion: camel.apache.org/v1
kind: Pipe
metadata:
name: aws-s3-source-pipe
annotations:
trait.camel.apache.org/camel.runtime-version: 3.6.0
spec:
integration:
dependencies:
- "camel:cloudevents"
source:
ref:
kind: Kamelet
apiVersion: camel.apache.org/v1
name: aws-s3-source
properties:
.....
```

Start with the CloudEvent dataref extension specification linked in the issue and the AWS S3 source example. Determine how this repository currently creates or handles CloudEvents, then define the integration points and tests needed to support dataref without sending large payloads.

Written by the indexing model from the issue text.