fix(k8s/infra): split infrastructure into controllers and configs stages

ClusterIssuer dry-run fails because cert-manager CRDs are not yet
installed when the single infrastructure Kustomization is applied.
Split into infrastructure-controllers (Helm charts that install CRDs)
and infrastructure-configs (CRD-dependent resources like ClusterIssuer)
with a dependency between them.

kubernetes/infrastructure/controllers/cert-manager/repository.yaml

@@ -0,0 +1,9 @@
+---
+apiVersion: source.toolkit.fluxcd.io/v1
+kind: HelmRepository
+metadata:
+  name: jetstack
+  namespace: flux-system
+spec:
+  interval: 1m0s
+  url: https://charts.jetstack.io