Investigate usability differences between Operator and Chart

In order to get to gitlab-org/gitlab#446075 we need to be aware of how easier or harder it is to install/maintain an Operator compared to helm chart and close the gap.

The first step was to provide a manifest list that doesn't require OLM. These are released with each release: https://gitlab.com/gitlab-org/gl-openshift/gitlab-runner-operator/-/releases/v1.27.1/downloads/operator.k8s.yaml