e2e detects prow and use images from ci-registry to eliminate mirror delays

Is your feature request related to a problem? Please describe.

See ci registry format in https://github.com/openshift/oadp-operator/issues/1233
Describe the solution you'd like

Describe alternatives you've considered

Additional context

unblocks usage with https://docs.ci.openshift.org/docs/how-tos/multi-pr-presubmit-testing/
and removes 1h mirror delay required to test latest changes from plugin repos.

Enhancement we had requested with multi-pr presubmit tests https://issues.redhat.com/browse/DPTP-4224 which were eventually closed cause we did not respond.

Another idea is to extend following substitutions list to include plugins

operator:
  bundles:
  - dockerfile_path: build/Dockerfile.bundle
  substitutions:
  - pullspec: quay.io/konveyor/oadp-operator:oadp-1.5
    with: oadp-operator-1.5

but it would require Containerfile in this repo for each plugin and produce "untested" images.

No files or tests are named. Start by tracing the repository's e2e and Prow presubmit configuration, then review the ci-registry format referenced in issue 1233 and the substitutions example. Done means Prow is detected, plugin images can use ci-registry images, and the one-hour mirror delay is removed for multi-PR presubmit testing.