build: move e2e dependencies into e2e/go.mod

Several packages are only used while running the e2e suite. These
packages are less important to update, as the they can not influence the
final executable that is part of the Ceph-CSI container-image.

By moving these dependencies out of the main Ceph-CSI go.mod, it is
easier to identify if a reported CVE affects Ceph-CSI, or only the
testing (like most of the Kubernetes CVEs).

Signed-off-by: Niels de Vos <ndevos@ibm.com>

e2e/vendor/github.com/google/cadvisor/watcher/watcher.go

@@ -0,0 +1,51 @@
+// Copyright 2016 Google Inc. 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 container defines types for sub-container events and also
+// defines an interface for container operation handlers.
+package watcher
+
+// SubcontainerEventType indicates an addition or deletion event.
+type ContainerEventType int
+
+const (
+	ContainerAdd ContainerEventType = iota
+	ContainerDelete
+)
+
+type ContainerWatchSource int
+
+const (
+	Raw ContainerWatchSource = iota
+)
+
+// ContainerEvent represents a
+type ContainerEvent struct {
+	// The type of event that occurred.
+	EventType ContainerEventType
+
+	// The full container name of the container where the event occurred.
+	Name string
+
+	// The watcher that detected this change event
+	WatchSource ContainerWatchSource
+}
+
+type ContainerWatcher interface {
+	// Registers a channel to listen for events affecting subcontainers (recursively).
+	Start(events chan ContainerEvent) error
+
+	// Stops watching for subcontainer changes.
+	Stop() error
+}