Convert openshift_oauth ingress to route

[Bobbins228]

Follow on from #407

WHY

As we move to create routes specifically for OpenShift users and ingresses for K8s users we should stick to using routes across the board for OpenShift clusters.

WHAT

What is being asked for?
Convert the ingress created when selecting openshift_oauth into a route.
Standardise the naming scheme of the routes to ray-dashboard-<cluster_name> and change route/ingress list requests to get requests using the standard naming scheme.

HOW

Convert the ingress object created here to a route object and replace necessary references from ingress to routes for openshift_oauth.

Update methods like _get_ingress_domain to instead use get_namespaced_custom_object and pass the new standard dashboard name to get the object.

DONE

Bullet point items for what should be completed