PR adds a new field(host) to the Argo CD CR .status. This is useful to retrieve the Argo CD server host name. 

While this feature works as expected when customers use Ingress on Kubernetes and Route on OpenShift, it does not work when a customer use Ingress on OpenShift.

To Reproduce
Steps to reproduce the behavior:
1. Get a OpenShift cluster.
2. Install and run the operator using `make install run`
3. Deploy the Argo CD instance using below example.
```
apiVersion: argoproj.io/v1alpha1
kind: ArgoCD
metadata:
  name: example-argocd
  labels:
    example: ingress
spec:
  server:
    ingress:
      enabled: true
    insecure: true
``` 
4. Wait for the operator to reconcile and create the pods.
5. Wait for the pods to move into running state.
6. Describe or Edit the Argo CD instance to identify that .status does not have any host field.

Expected behavior
host details should be updated in the Argo CD CR .status.

As per my initial analysis, I have noticed that operator adds a Ingress Class annotation that is specific to Nginx Ingress Controller. By default the Ingress controller deployed in the OpenShift clusters is HAProxy, so the annotation hard coded [here](https://github.com/argoproj-labs/argocd-operator/blob/f67e04db076c8700260e100721391e8bfb570da3/controllers/argocd/ingress.go#L33) should be removed. 

One of the below conditions has to be met for the HA Proxy Ingress controller to read any Ingress resource
https://haproxy-ingress.github.io/docs/configuration/keys/#class-matter

A user has to be provided with an option to define their own Ingress class through the Argo CD CR.