[feature] Requirements to support Cluster Topology SNO

USER STORY:

As a partner I would like to be able to run OPCT on OCP SNO (Single Node Openshift) or SingleReplica, so I can certify this topology in my catalog.

DESCRIPTION:

Feature to evaluate running on SNO:

• Run OPCT mode <default>
• Run OPCT mode upgrade

Required:

• Steps to run OPCT in SNO in regular mode
• Steps to run OPCT in SNO in upgrade mode
• Study of running OPCT in SNO outside the cluster, and options

Nice to have:

...

ACCEPTANCE CRITERIA:

• Document with steps to run OPCT in SNO, describing any limitations and risks it might have
• OpenShift CI workflow running at least one monthly periodic job validation the documentation steps (see  [1] for reference adding jobs to CI)

ENGINEERING DETAILS:

• Tracking email subject: "OPCT - PoC upgrade feature (request for review)"
• https://docs.openshift.com/container-platform/4.12/operators/operator_sdk/osdk-ha-sno.html
• https://docs.openshift.com/container-platform/4.12/installing/installing_sno/install-sno-installing-sno.html
• Playbooks to install SNO (infra + node) with high performance disk and cost-effective mode: https://github.com/mtulio/ansible-collection-okd-installer/pull/24
•  [1] Reference of adding OPCT periodics on OCP CI: https://github.com/openshift/release/pull/38271