Add labels for better application grouping and icons in OpenShift Topology View

[rm3l]

User Story

As a user of the Operator on OpenShift, I want, in the Topology View, to be able to distinguish the resources created and managed by the Operator from the rest of my other resources, So that I can have a clear separation between different apps in the same namespace.

While doing a quick test of the RHDH image on OpenShift, I noticed that resources from the Helm Chart are currently grouped and have proper icons displayed for PostgreSQL and Backstage. But resources managed by the Operator are using a generic icon and are floating, making it look like they are completely unrelated.
See the screenshot below - Helm resources on the left, and resources created by the operator on the right:

Acceptance Criteria

• It should group the resources created by the Operator. From this OpenShift doc, it seems that we should add the app.kubernetes.io/part-of label. Value could be the CR name.
• It should add the correct labels to have the icons show up. From this OpenShift doc, it seems that it looks for the app.openshift.io/runtime label, followed by app.kubernetes.io/name label against a predefined set of icons: https://github.com/openshift/console/blob/master/frontend/public/components/catalog/catalog-item-icon.tsx
• It should connect the Backstage and PostgreSQL nodes, using the app.openshift.io/connects-to annotation

Notes

• Doc on labels and annotations used for the Topology View: https://docs.openshift.com/container-platform/4.14/applications/odc-viewing-application-composition-using-topology-view.html#odc-labels-and-annotations-used-for-topology-view_viewing-application-composition-using-topology-view
• Related to Add labels and annotations recommended for OpenShift/Kubernetes applications to all resources created by the Operator #32
• Related to Test and make sure the default CR configuration works properly on OpenShift #31

[rm3l]

I just noticed that Openshift does group the resources when creating a Backstage instance from the list of installed operators, which was my main concern here. It also displays the RHDH icon on both the Backstage and Postgresql pods, which is fine right now.

Lowering the priority, but we would still need to use the right icon for Postgresql and set the right annotation to connect both pods.

[rm3l]

JIRA issue: https://issues.redhat.com/browse/RHIDP-3660

/close