Trigger BrokerRef and Cross namespace references

[cmellard]

Problem
Kafka Broker does not currently support cross namespace triggers

Persona:
Event Consumer - Development teams trying to manage their own triggers/consumer groups

Exit Criteria
We can create a Trigger for a Kafka Broker in a namespace other than the Broker namespace and reconciliation of the Trigger/CG etc succeeds.

Had a quick scan/search of the issues and code base but couldn't find anything discussing this. For reference I'm talking about this BrokerRef field in the Trigger

type TriggerSpec struct {
	// Broker is the broker that this trigger receives events from.
	Broker string `json:"broker,omitempty"`

	// BrokerRef is the broker that is used for cross-namespace referencing.
	BrokerRef *duckv1.KReference `json:"brokerRef,omitempty"`

https://knative.dev/docs/eventing/features/cross-namespace-event-links/

[pierDipi]

@cmellard thanks for reporting!

Would you be interested in contributing this feature?
If you’re interested, I’d be happy to provide any additional information or resources you might need to get started. We have documentation available (contributing doc), and I’m also here or on CNCF Slack to answer any questions you might have.

/triage accepted