Support Multiple Knative Sinks

[ricardozanini]

Description

currently due to the K_SINK var injection, we can only support one sinkbinding per deployment. To support the flexibility of multiple event destinations from producers within single deployment. We need to find out a way to support multiple sinks.

Implementation ideas

No response

[jianrongzhang89]

@ricardozanini only one sinkbinding can be allowed for an application. Creating multiple sinkbindings against the same application can lead to issues for the cluster (knative/eventing#5749). Hence I think this issue should be rejected.