Concierge should support OpenShift clusters

[enj]

Given I have an Openshift 4.x cluster
When I install the Pinniped Concierge following website docs
Then I see that it installs correctly
And I see that the CredentialIssuer enters a successful status
And when I configure a Concierge-based login
Then the login succeeds

Notes

Is your feature request related to a problem? Please describe.

Pinniped should work on OpenShift clusters.

Describe the solution you'd like

The location of the signing key is different in OpenShift clusters. We should simply be able to get it from the Kube API at a specific location without needing to run a pod (there is an operator that runs the KCM static pods and it has all the secrets in the Kube API before rendering the static pod manifests).

• How will this project improvement be tested?

Run it on OpenShift and make sure auth works.