improve Cilium metrics support (#6513)

Signed-off-by: Arthur Outhenin-Chalandre <arthur@cri.epita.fr>

roles/network_plugin/cilium/templates/cilium-deploy.yml.j2

@@ -20,6 +20,11 @@ spec:
     type: RollingUpdate
   template:
     metadata:
+{% if cilium_enable_prometheus %}
+      annotations:
+        prometheus.io/port: "6942"
+        prometheus.io/scrape: "true"
+{% endif %}
       labels:
         io.cilium/app: operator
         name: cilium-operator
@@ -93,6 +98,13 @@ spec:
           image: "{{ cilium_operator_image_repo }}:{{ cilium_operator_image_tag }}"
           imagePullPolicy: {{ k8s_image_pull_policy }}
           name: cilium-operator
+{% if cilium_enable_prometheus %}
+          ports:
+            - containerPort: 6942
+              hostPort: 6942
+              name: prometheus
+              protocol: TCP
+{% endif %}
           livenessProbe:
             httpGet:
 {% if cilium_enable_ipv4 %}