Rename "auto" subcommands to "image"

This means all the sub-subcommands can drop the `image-` prefix,
making them shorter and more fluent.

E.g.,

    flux create image policy

rather than

    flux create auto image-policy

Signed-off-by: Michael Bridgen <michael@weave.works>

cmd/flux/export_image_policy.go

@@ -0,0 +1,72 @@
+/*
+Copyright 2020 The Flux authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package main
+
+import (
+	"github.com/spf13/cobra"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+
+	imagev1 "github.com/fluxcd/image-reflector-controller/api/v1alpha1"
+)
+
+var exportImagePolicyCmd = &cobra.Command{
+	Use:   "policy [name]",
+	Short: "Export ImagePolicy resources in YAML format",
+	Long:  "The export image policy command exports one or all ImagePolicy resources in YAML format.",
+	Example: `  # Export all ImagePolicy resources
+  flux export image policy --all > image-policies.yaml
+
+  # Export a specific policy
+  flux export image policy alpine1x > alpine1x.yaml
+`,
+	RunE: exportCommand{
+		object: imagePolicyAdapter{&imagev1.ImagePolicy{}},
+		list:   imagePolicyListAdapter{&imagev1.ImagePolicyList{}},
+	}.run,
+}
+
+func init() {
+	exportImageCmd.AddCommand(exportImagePolicyCmd)
+}
+
+// Export returns a ImagePolicy value which has extraneous information
+// stripped out.
+func exportImagePolicy(item *imagev1.ImagePolicy) interface{} {
+	gvk := imagev1.GroupVersion.WithKind(imagev1.ImagePolicyKind)
+	export := imagev1.ImagePolicy{
+		TypeMeta: metav1.TypeMeta{
+			Kind:       gvk.Kind,
+			APIVersion: gvk.GroupVersion().String(),
+		},
+		ObjectMeta: metav1.ObjectMeta{
+			Name:        item.Name,
+			Namespace:   item.Namespace,
+			Labels:      item.Labels,
+			Annotations: item.Annotations,
+		},
+		Spec: item.Spec,
+	}
+	return export
+}
+
+func (ex imagePolicyAdapter) export() interface{} {
+	return exportImagePolicy(ex.ImagePolicy)
+}
+
+func (ex imagePolicyListAdapter) exportItem(i int) interface{} {
+	return exportImagePolicy(&ex.ImagePolicyList.Items[i])
+}