feat: migrate cert-manager from Terraform to ArgoCD (#42)

- Add cert-manager base ArgoCD application with namespace, RBAC resources
- Create cert-manager overlay for au-syd1 with Helm chart configuration
- Update platform ApplicationSet to include cert-manager deployment
- Configure cert-manager v1.19.2 with jetstack Helm repository
- Maintain one-to-one migration from Terraform configuration

Reviewed-on: #42

apps/base/cert-manager/clusterrole.yaml

@@ -0,0 +1,12 @@
+---
+apiVersion: rbac.authorization.k8s.io/v1
+kind: ClusterRole
+metadata:
+  name: cert-manager-vault-token-creator
+  labels:
+    app.kubernetes.io/name: "cert-manager-config"
+    app.kubernetes.io/instance: "cert-manager-config"
+rules:
+- apiGroups: [""]
+  resources: ["serviceaccounts/token"]
+  verbs: ["create"]

apps/base/cert-manager/clusterrolebinding.yaml

@@ -0,0 +1,16 @@
+---
+apiVersion: rbac.authorization.k8s.io/v1
+kind: ClusterRoleBinding
+metadata:
+  name: cert-manager-vault-token-creator
+  labels:
+    app.kubernetes.io/name: "cert-manager-config"
+    app.kubernetes.io/instance: "cert-manager-config"
+roleRef:
+  apiGroup: rbac.authorization.k8s.io
+  kind: ClusterRole
+  name: cert-manager-vault-token-creator
+subjects:
+- kind: ServiceAccount
+  name: cert-manager
+  namespace: cert-manager

apps/base/cert-manager/kustomization.yaml

@@ -0,0 +1,9 @@
+---
+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+
+resources:
+  - namespace.yaml
+  - serviceaccount.yaml
+  - clusterrole.yaml
+  - clusterrolebinding.yaml

apps/base/cert-manager/namespace.yaml

@@ -0,0 +1,5 @@
+---
+apiVersion: v1
+kind: Namespace
+metadata:
+  name: cert-manager

apps/base/cert-manager/serviceaccount.yaml

@@ -0,0 +1,11 @@
+---
+apiVersion: v1
+kind: ServiceAccount
+metadata:
+  name: vault-issuer
+  namespace: cert-manager
+  labels:
+    app.kubernetes.io/name: "cert-manager-config"
+    app.kubernetes.io/instance: "cert-manager-config"
+    app.kubernetes.io/component: "vault-issuer"
+automountServiceAccountToken: true