pkg/resource: add StoreCurrentRV

[sttts]

Description of your changes

To detect when an Apply is a no-op or not. Compare crossplane/crossplane#4572.

origRV := ""
if err := r.client.Apply(ctx, crd, resource.MustBeControllableBy(d.GetUID()), resource.StoreCurrentRV(&origRV)); err != nil {
    return reconcile.Result{}, err
}
if crd.GetResourceVersion() != origRV {
    r.record.Event(d, event.Normal(reasonEstablishXR, fmt.Sprintf("Applied composite resource CustomResourceDefinition: %s", crd.GetName())))
}

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