VOL-1460: Docker builds now use common base image.  Also Documentation Update.

Modified all docker files to use a base build that copies in vendor and
other common GOPATH items.  Then each dependant Dockerfile
uses the base and only copies in golang source needed to build.

Also grab updated lock file and vendor items missing (from a dep ensure)
for build to work.

Change-Id: I6047847c2c186a24d1f223b1a4dfab39ab381a92
diff --git a/vendor/google.golang.org/grpc/credentials/tls13.go b/vendor/google.golang.org/grpc/credentials/tls13.go
new file mode 100644
index 0000000..ccbf35b
--- /dev/null
+++ b/vendor/google.golang.org/grpc/credentials/tls13.go
@@ -0,0 +1,30 @@
+// +build go1.12
+
+/*
+ *
+ * Copyright 2019 gRPC 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 credentials
+
+import "crypto/tls"
+
+// This init function adds cipher suite constants only defined in Go 1.12.
+func init() {
+	cipherSuiteLookup[tls.TLS_AES_128_GCM_SHA256] = "TLS_AES_128_GCM_SHA256"
+	cipherSuiteLookup[tls.TLS_AES_256_GCM_SHA384] = "TLS_AES_256_GCM_SHA384"
+	cipherSuiteLookup[tls.TLS_CHACHA20_POLY1305_SHA256] = "TLS_CHACHA20_POLY1305_SHA256"
+}