Write OpenShift documentation for namespace-scoped Argo Rollouts installs
Write the OpenShift documentation that describes the required changes to enable namespace-scoped Argo Rollouts installs.

Also verify that the existing documentation is updated to be consistent with cluster-scoped Rollouts installs.

Note: Because this this involves a change to the API behaviour, we should make sure this is documented by docs within the release notes (for example example, using 'error box styling')