Add Flux sync manifests

clusters/testing/flux-system/gotk-sync.yaml

+# This manifest was generated by flux. DO NOT EDIT.
+---
+apiVersion: source.toolkit.fluxcd.io/v1
+kind: GitRepository
+metadata:
+  name: flux-system
+  namespace: flux-system
+spec:
+  interval: 1m0s
+  ref:
+    branch: main
+  secretRef:
+    name: flux-system
+  url: https://git.wechange.de/gl/code/k8s-cluster.git
+---
+apiVersion: kustomize.toolkit.fluxcd.io/v1
+kind: Kustomization
+metadata:
+  name: flux-system
+  namespace: flux-system
+spec:
+  interval: 10m0s
+  path: ./clusters/testing
+  prune: true
+  sourceRef:
+    kind: GitRepository
+    name: flux-system

clusters/testing/flux-system/kustomization.yaml

+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+resources:
+- gotk-components.yaml
+- gotk-sync.yaml