feat: move kubernetes dir into templates to support jinja2 across all files (#831)

template/templates/kubernetes/flux/vars/cluster-secrets.sops.yaml.j2

@@ -0,0 +1,10 @@
+---
+apiVersion: v1
+kind: Secret
+metadata:
+  name: cluster-secrets
+  namespace: flux-system
+stringData:
+  SECRET_DOMAIN: "{{ bootstrap_cloudflare_domain }}"
+  SECRET_ACME_EMAIL: "{{ bootstrap_acme_email }}"
+  SECRET_CLOUDFLARE_TUNNEL_ID: "{{ bootstrap_cloudflare_tunnel_id }}"