feat: Migrate sys applications to helmfile

Move most of helmfiles into temp to test only velero.

File structure:

```bash
/
├── helmfile.d/                                                 # Helmfiles, *.yaml.gotmpl
├── charts/                                                     # Our own charts, e.g `Atlantis`
├── values                                                      # Values for helmfiles
│   ├── <chart>
│   │   ├── values.yaml.gotmpl                                  # Values to be templated in `values/`
│   │   ├── kustomize                                           # Kustomizations per environment
│   │   ├── manifests                                           # Raw manifests
│   │   │   ├── <chart>.yaml                                    # Argo App for bootstrap
│   │   │   ├── dashboards                                      # Grafana dashboards
│   │   │   │   └── <chart>-metrics.yaml
│   │   │   └── policies                                        # Cilium and Kyverno policies
│   │   │       ├── CiliumNetworkPolicy-allow-api-server.yaml
│   │   │       └── KyvernoPolicy-regred-secret.yaml
│   │   └── values                                              # Values for each environment
│   │       ├── <chart>-staging.yaml.gotmpl                     # Values for staging environment
│   │       ├── <chart>-prod.yaml.gotmpl                        # Values for prod environment
│   │       └── <chart>.yaml.gotmpl                             # Standard values for all environments
│   │
│   ├── values.yaml                                             # Standard values for all cluster
│   ├── values-oceanbox.yaml                                    # Values overrides for oceanbox
│   ├── values-ekman.yaml                                       # Values overrides for ekman
```

shell.nix

@@ -28,7 +28,10 @@ pkgs.mkShellNoCC {
     helmWrap
     helmfileWrap
     helmfile-nix
+
+    kubectl-cnpg
+    kubectl-neat
   ];
 
-  CLUSTER_NAME = "oceanbox";
+  ARGOCD_ENV_CLUSTER_NAME = "oceanbox";
 }