feat(argocd): Implement App of Apps Pattern

Introduced the ArgoCD app of applications pattern to improve the
management and scalability of ArgoCD configurations:

- Added argocd.yaml to define the main ArgoCD application.
- Added argo-applications.yaml to manage nested applications.
- Updated kustomization.yaml to include argo-applications.yaml in
  the resources list.

Author: ssoriche

argocd-applications/do/argocd.yaml

@@ -0,0 +1,18 @@
+apiVersion: argoproj.io/v1alpha1
+kind: Application
+metadata:
+  name: argocd
+  namespace: argocd
+spec:
+  project: default
+  source:
+    repoURL: https://github.com/metacpan/metacpan-k8s
+    targetRevision: main
+    path: platform/argocd/do
+  destination:
+    server: "https://kubernetes.default.svc"
+    namespace: argocd
+  syncPolicy:
+    automated:
+      prune: true
+      selfHeal: false

platform/argocd/do/argo-applications.yaml

@@ -0,0 +1,18 @@
+apiVersion: argoproj.io/v1alpha1
+kind: Application
+metadata:
+  name: argocd-applications
+  namespace: argocd
+spec:
+  project: default
+  source:
+    repoURL: https://github.com/metacpan/metacpan-k8s
+    targetRevision: main
+    path: "/argocd-applications/do/"
+  destination:
+    server: "https://kubernetes.default.svc"
+    namespace: argocd
+  syncPolicy:
+    automated:
+      prune: true
+      selfHeal: false

platform/argocd/do/kustomization.yaml

@@ -6,4 +6,4 @@ resources:
   - ./github_auth_secret.yaml
   - ./../patches/
   - ./ingress.yaml
-
+  - ./argo-applications.yaml