Remove not implemented WebHooks

[guettli]

/kind feature

Some CRDs have a webHook, although they are not implemented.

For example:

type hetznerBareMetalRemediationWebhook struct{}

....

func (*hetznerBareMetalRemediationWebhook) Default(_ context.Context, _ runtime.Object) error {
	return nil
}

The related methods (for Default/Create/Update/Delete) exist, but they all do nothing.

We can remove that code.

Above type is only an example. Afaik there are several types without a webhook implementation.