[ci skip] Fix code review findings: correct Alertmanager URL, add atomic to Loki, remove dead minio NFS export, update design doc

modules/kubernetes/monitoring/loki.tf

@@ -7,6 +7,7 @@ resource "helm_release" "loki" {
   chart      = "loki"
 
   values  = [templatefile("${path.module}/loki.yaml", {})]
+  atomic  = true
   timeout = 300
 
   depends_on = [kubernetes_config_map.loki_alert_rules]

modules/kubernetes/monitoring/loki.yaml

@@ -34,7 +34,7 @@ loki:
       type: local
       local:
         directory: /loki/rules
-    alertmanager_url: http://alertmanager.monitoring.svc.cluster.local:9093
+    alertmanager_url: http://prometheus-alertmanager.monitoring.svc.cluster.local:9093
     ring:
       kvstore:
         store: inmemory