Add a presubmit job that configures a set of PlatformOperators before cluster creation

Goal: Introduce a new presubmit job that injects the requisite FeatureGate and a set of valid PlatformOperator YAML manifests with the rest of the cluster's Kubernetes manifests. This should help weed out any issues when configuring phase 0

Notes:

• This should be an optional check
• We may be introducing maintenance burden over time given the configured package name in the sample PlatformOperator YAML manifest could change during the 4.12 timeframe

Resources:

• https://docs.ci.openshift.org/docs/how-tos/adding-changing-step-registry-content/
• https://docs.ci.openshift.org/docs/architecture/step-registry/#registry-layout-and-naming-convention

AC:

• Create a new CI workflow step that injects a FeatureGate + PlatformOperator YAML manifest with the rest of the cluster's Kubernetes manifests
• Introduce a new prowjob that runs this custom CI workflow step and runs the o/platform-operators e2e suite