explicit kubelet config key in Node.Spec.ConfigSource.ConfigMap

This makes the Kubelet config key in the ConfigMap an explicit part of
the API, so we can stop using magic key names.

As part of this change, we are retiring ConfigMapRef for ConfigMap.

pkg/kubelet/apis/kubeletconfig/zz_generated.deepcopy.go

@@ -246,3 +246,29 @@ func (in *KubeletX509Authentication) DeepCopy() *KubeletX509Authentication {
 	in.DeepCopyInto(out)
 	return out
 }
+
+// DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.
+func (in *SerializedNodeConfigSource) DeepCopyInto(out *SerializedNodeConfigSource) {
+	*out = *in
+	out.TypeMeta = in.TypeMeta
+	in.Source.DeepCopyInto(&out.Source)
+	return
+}
+
+// DeepCopy is an autogenerated deepcopy function, copying the receiver, creating a new SerializedNodeConfigSource.
+func (in *SerializedNodeConfigSource) DeepCopy() *SerializedNodeConfigSource {
+	if in == nil {
+		return nil
+	}
+	out := new(SerializedNodeConfigSource)
+	in.DeepCopyInto(out)
+	return out
+}
+
+// DeepCopyObject is an autogenerated deepcopy function, copying the receiver, creating a new runtime.Object.
+func (in *SerializedNodeConfigSource) DeepCopyObject() runtime.Object {
+	if c := in.DeepCopy(); c != nil {
+		return c
+	}
+	return nil
+}