remove the channel-broker configs and release files

[vaikas]

Remove the configurations and release files that still have the channel based broker. The deployment we released last time turned it to zero. There's no need to continue to ship with that.

Proposed Changes

• Remove channel based broker from the release scripts and associated configs.

Release Note

- 🧽 Update or clean up current behavior
action-required. You must manually delete the (previously scaled to 0 deployment):
metadata:	
  name: broker-controller	
  namespace: knative-eventing

Docs

[pierDipi]

/lgtm

related: #3548

[knative-prow-robot]

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This pull-request has been approved by: pierDipi, vaikas

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