Move CLI related packages into internal (#697)

We don't want people to import these packages, so move these out into
private packages.

internal/manager/doc.go

@@ -0,0 +1,21 @@
+// Copyright © 2017 The virtual-kubelet 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 manager provides access to kubernetes resources for providers.
+//
+// DEPRECATION WARNING:
+// Though this package is still in use, it should be considered deprecated as it
+// is just wrapping a k8s client and not much else.
+// Implementers should look at replacing their use of this with something else.
+package manager