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/Makefile b/Makefile
index b0bf2be..257d372 100644
--- a/Makefile
+++ b/Makefile
@@ -90,25 +90,25 @@
 endif
 	docker build $(DOCKER_BUILD_ARGS) -t base:latest -f docker/Dockerfile.base .
 
-afrouter:
+afrouter: base
 	docker build $(DOCKER_BUILD_ARGS) -t ${REGISTRY}${REPOSITORY}afrouter:${TAG} -f docker/Dockerfile.arouter .
 
-afrouterTest:
+afrouterTest: base
 	docker build $(DOCKER_BUILD_ARGS) -t ${REGISTRY}${REPOSITORY}afroutertest:${TAG} -f docker/Dockerfile.arouterTest .
 
-arouterd:
+arouterd: base
 	docker build $(DOCKER_BUILD_ARGS) -t ${REGISTRY}${REPOSITORY}afrouterd:${TAG} -f docker/Dockerfile.arouterd .
 
-rw_core:
+rw_core: base
 	docker build $(DOCKER_BUILD_ARGS) -t ${REGISTRY}${REPOSITORY}voltha-rw-core:${TAG} -f docker/Dockerfile.rw_core .
 
-ro_core:
+ro_core: base
 	docker build $(DOCKER_BUILD_ARGS) -t ${REGISTRY}${REPOSITORY}voltha-ro-core:${TAG} -f docker/Dockerfile.ro_core .
 
-simulated_olt:
+simulated_olt: base
 	docker build $(DOCKER_BUILD_ARGS) -t ${REGISTRY}${REPOSITORY}voltha-adapter-simulated-olt:${TAG} -f docker/Dockerfile.simulated_olt .
 
-simulated_onu:
+simulated_onu: base
 	docker build $(DOCKER_BUILD_ARGS) -t ${REGISTRY}${REPOSITORY}voltha-adapter-simulated-onu:${TAG} -f docker/Dockerfile.simulated_onu .
 
 # end file