Add example of KSUpackage for crossplane

---

# Helm release for controller

apiVersion: helm.toolkit.fluxcd.io/v2beta1

kind: HelmRelease

metadata:

  name: crossplane

  namespace: crossplane-system

spec:

  chart:

    spec:

      chart: crossplane

      reconcileStrategy: ChartVersion

      sourceRef:

        kind: HelmRepository

        name: crossplane-stable

        namespace: crossplane-system

  install:

    createNamespace: true

  interval: 30s

  releaseName: crossplane

  targetNamespace: crossplane-system

---

apiVersion: source.toolkit.fluxcd.io/v1beta2

kind: HelmRepository

metadata:

  name: crossplane-stable

  namespace: crossplane-system

spec:

  interval: 30s

  url: https://charts.crossplane.io/stable

apiVersion: kustomize.toolkit.fluxcd.io/v1

kind: Kustomization

metadata:

  name: crossplane-controller

  namespace: crossplane-system

spec:

  interval: 1h

  retryInterval: 1m

  timeout: 5m

  sourceRef:

    kind: GitRepository

    name: sw-catalogs

    namespace: flux-system

  path: ./infra-controllers/crossplane/controller/manifests

  prune: true

apiVersion: v1

kind: Namespace

metadata:

  name: crossplane-system