REFACTOR(repo): restructure monitoring folder

- and add namespace resou...
- Remove argocd/, helm-values/, ingress/ subdirectories
- Move files to parent directory (argocd.yaml, helm-values.yaml,
  ingress.yaml)
- Update helm valueFiles paths in ArgoCD Applications
- Add namespace.yaml to all applications with Goldilocks labels
- Update destination namespaces to match folder names
- Update kustomization.yaml files to reference new structure

prometheus/kustomization.yaml

@@ -2,6 +2,8 @@ apiVersion: kustomize.config.k8s.io/v1beta1
 kind: Kustomization
 
 resources:
-  # ArgoCD Application 리소스는 infrastructure/kustomization.yaml에서 관리
-  # - argocd/prometheus.yaml
+  # ArgoCD Application 리소스는 monitoring/kustomization.yaml에서 관리
+  # - argocd.yaml
+
+  - namespace.yaml
   - vault/postgresql-password.yaml