We need to create releases the same way upstream does, resulting in a single manifest file that references our internal images and includes whatever additional fixes required to successfully run on OpenShift.

See https://github.com/knative/test-infra/tree/master/scripts#using-the-releasesh-helper-script

Acceptance Criteria:

• The YAML used by our operator to install Knative Serving is no longer manually edited but automatically created based on upstream YAML