Ability to configure the Red Hat SSO/Keycloak host name

1. Proposed title of this feature request
Ability to configure the Red Hat SSO/Keycloak hostname

2. What is the nature and description of the request?
When using Ingress Controller sharding it's important that route name can be specified as domain respectively DNSsuffix can change depending on what IngressController the route is exposed too. The ArgoCD server hostname can already be specified. Now the same needs to be possible for the sso part, where Red Hat SSO/Keycloak is being used.

3. Why does the customer need this? (List the business requirements here)
With Ingress Controller sharding we need to be able to either automatically detect the DNSsuffix configured for the IngressController the route is exposed too and use that or otherwise allow configure it in the ArgoCD custom resource. Allowing to configure it will provide more flexibility and therefore is the preferred approach.

apiVersion: argoproj.io/v1alpha1
kind: ArgoCD
metadata:
  name: example-argocd
  namespace: foobar
[...]
spec:
  server:
    host: argocd-foobar.apps.example.com
    route:
      enabled: true
  sso:
    provider: keycloak
      host: sso-foobar.apps.example.com <<-- something like that

The above is an example how the ArgoCD could potentially look like to configure sso route name.

4. List any affected packages or components.

• OpenShift GitOps