Quay docs should provide guide to configure OIDC provider

Description:

This is a doc issue that related to how to configure OIDC provider to authenticate in Quay, now when Quay Customers want to use OIDC provider, like Keycloak to authenticate in Quay, they need related Docs to do required configuration from SSO server(Keyclaok) side, and what configurations need to do on Quay.

Pls provide the required docs in Quay official guide, attached the docs that QE used to perform testing for reference.

https://docs.google.com/document/d/1eYKFT9umf-YUkt_QAO2q-eRL9kisHn4IyPY1e67XpNM/edit 

Callback URLs for this service:  
https://quay1130-quay-quay340.apps.quay-413.qe.devcluster.openshift.com/oauth2/sss/callback 
https://quay1130-quay-quay340.apps.quay-413.qe.devcluster.openshift.com/oauth2/sss/callback/attach 
https://quay1130-quay-quay340.apps.quay-413.qe.devcluster.openshift.com/oauth2/sss/callback/cli