This PR does the following things:

1. add new registry api under resources.kubesphere.io/v1alpha3
2. deprecate registry api v1alpha2

Registry API v1alpha2 uses docker client to authenticate image registry
secret, which depends on docker.sock. We used to mount host
`/var/run/docker.sock` to deployment. It will prevent us imgrating to
containerd since no `docker.sock` exists. Registry API v1alpha3 comes to
rescure, it wraps library go-containerregistry and compatible with
docker registry, Harbor etc.

vendor/github.com/google/go-containerregistry/pkg/v1/remote/delete.go

@@ -0,0 +1,57 @@
+// Copyright 2018 Google LLC All Rights Reserved.
+//
+// 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 remote
+
+import (
+	"fmt"
+	"net/http"
+	"net/url"
+
+	"github.com/google/go-containerregistry/pkg/name"
+	"github.com/google/go-containerregistry/pkg/v1/remote/transport"
+)
+
+// Delete removes the specified image reference from the remote registry.
+func Delete(ref name.Reference, options ...Option) error {
+	o, err := makeOptions(ref.Context(), options...)
+	if err != nil {
+		return err
+	}
+	scopes := []string{ref.Scope(transport.DeleteScope)}
+	tr, err := transport.NewWithContext(o.context, ref.Context().Registry, o.auth, o.transport, scopes)
+	if err != nil {
+		return err
+	}
+	c := &http.Client{Transport: tr}
+
+	u := url.URL{
+		Scheme: ref.Context().Registry.Scheme(),
+		Host:   ref.Context().RegistryStr(),
+		Path:   fmt.Sprintf("/v2/%s/manifests/%s", ref.Context().RepositoryStr(), ref.Identifier()),
+	}
+
+	req, err := http.NewRequest(http.MethodDelete, u.String(), nil)
+	if err != nil {
+		return err
+	}
+
+	resp, err := c.Do(req.WithContext(o.context))
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+
+	return transport.CheckError(resp, http.StatusOK, http.StatusAccepted)
+}