Move defaulting from webhooks to CRD

[kvaps]

Consider replacing defaulting webhook with native CRD validation:

etcd-operator/api/v1alpha1/etcdcluster_webhook.go

Lines 45 to 47 in 94c538d

	if r.Spec.Replicas == 0 {
	r.Spec.Replicas = 3
	}

etcd-operator/api/v1alpha1/etcdcluster_types.go

Line 33 in 94c538d

// +kubebuilder:default:=3

[kvaps]

Also shouldn't we use pointers for those values to explicitly specify value if it wasn't specified?

Otherwise it might be blocking to scale etcd cluster to 0 replicas.

[sircthulhu]

After tests I found out annotation // +kubebuilder:default:=3 only adds data to CRD, it does not protect us from creating CR EtcdCluster with zero replicas

[kvaps]

It's okay, I think we're should have an opportunity to start with 0