Fix: Add Server Ingress checks to apply the changes in case it exists

[nmirasch]

What type of PR is this?
/kind bug

What does this PR do / why we need it:
This PR adds logic to reconcile Server Ingress related changes in case it exists previously.

Which issue(s) this PR fixes:

Fixes #558
Fixes: https://issues.redhat.com/browse/GITOPS-5386

How to test changes / Special notes to the reviewer:
I performed an upgrade test as follows:

1. Ran make run
2. Created an ArgoCD CR.
3. Check the Server Service Type is ClusterIP (by default)
4. Do a kubectl apply on something like:

apiVersion: argoproj.io/v1alpha1
kind: ArgoCD
metadata:
  name: argocd
spec:
  server:
    ingress:
      enabled: true

5. Followed by a kubectl apply on something like:

apiVersion: argoproj.io/v1alpha1
kind: ArgoCD
metadata:
  name: argocd
spec:
  server:
    host: foo.bar
    ingress:
      enabled: true

6. Check the ingress have been updated with the new host value when describing the ingress

[svghadi]

LGTM. Thanks @nmirasch.

[anandrkskd]

/lgtm