Add IngressClass resource and update references to spec.ingressClassName across templates, examples, and documentation for consistency and backward compatibility

- Introduced new IngressClass resource in Helm templates to define `easyhaproxy` as the default ingress class.
- Updated Kubernetes examples to replace `easyhaproxy-ingress` with `easyhaproxy` as the ingress class name.
- Enhanced processor logic to support both the new `spec.ingressClassName` field and the deprecated `kubernetes.io/ingress.class` annotation.
- Revised documentation to reflect the changes and ensure alignment with Kubernetes recommendations.

helm/easyhaproxy/values.yaml

@@ -31,6 +31,13 @@ serviceAccount:
   annotations: {}
   name: ""
 
+# IngressClass configuration
+ingressClass:
+  # Create IngressClass resource
+  create: true
+  # Additional annotations for the IngressClass
+  annotations: {}
+
 podAnnotations: {}
 
 podSecurityContext: {}