feat: Add cert-manager as dependency for Rancher

Rancher requires cert-manager when managing its own TLS (not tls:external).
Added cert-manager HelmRelease with CRDs enabled.

infrastructure/addons/cert-manager/helmrelease-cert-manager.yaml

@@ -0,0 +1,34 @@
+apiVersion: helm.toolkit.fluxcd.io/v2
+kind: HelmRelease
+metadata:
+  name: cert-manager
+  namespace: flux-system
+spec:
+  interval: 10m
+  targetNamespace: cert-manager
+  chart:
+    spec:
+      chart: cert-manager
+      version: "v1.17.2"
+      sourceRef:
+        kind: HelmRepository
+        name: jetstack
+        namespace: flux-system
+  install:
+    createNamespace: true
+    remediation:
+      retries: 3
+  upgrade:
+    remediation:
+      retries: 3
+  values:
+    crds:
+      enabled: true
+    replicaCount: 1
+    resources:
+      requests:
+        cpu: 50m
+        memory: 128Mi
+      limits:
+        cpu: 250m
+        memory: 256Mi