web: Extend production server list in production

So some views are better cached in different instances.

Refs. swh/infra/sysadm-environment#5183

swh/templates/web/configmap.yaml

@@ -14,6 +14,12 @@ data:
       {{- range $host := $hosts }}
       - {{ $host }}
       {{- end }}
+    {{- if and .Values.environment (eq .Values.environment "production") }}
+    production_server_names:
+      {{- range $host := $hosts }}
+      - {{ $host }}
+      {{- end }}
+    {{- end }}
     {{- include "swh.service.fromYaml" (dict "service" "storage"
                                              "configurationRef" .Values.web.storageConfigurationRef
                                              "Values" .Values) | nindent 4 }}