feat: improve docs and cluster dir

cluster/base/flux-system/gotk-sync.yaml

@@ -0,0 +1,31 @@
+---
+apiVersion: source.toolkit.fluxcd.io/v1beta1
+kind: GitRepository
+metadata:
+  name: flux-system
+  namespace: flux-system
+spec:
+  interval: 1m0s
+  ref:
+    branch: main
+  secretRef:
+    name: flux-system
+  url: ssh://git@github.com/$BOOTSTRAP_GITHUB_REPOSITORY
+---
+apiVersion: kustomize.toolkit.fluxcd.io/v1beta1
+kind: Kustomization
+metadata:
+  name: flux-system
+  namespace: flux-system
+spec:
+  interval: 10m0s
+  path: ./cluster/base
+  prune: true
+  sourceRef:
+    kind: GitRepository
+    name: flux-system
+  validation: client
+  decryption:
+    provider: sops
+    secretRef:
+      name: sops-gpg