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/docker/Dockerfile.arouter b/docker/Dockerfile.arouter
index 329fc68..5401514 100644
--- a/docker/Dockerfile.arouter
+++ b/docker/Dockerfile.arouter
@@ -3,43 +3,31 @@
 
 FROM base AS build-env
 
-# Copy files
-ADD rw_core $GOPATH/src/github.com/opencord/voltha-go/rw_core
-ADD common $GOPATH/src/github.com/opencord/voltha-go/common
-ADD db $GOPATH/src/github.com/opencord/voltha-go/db
-ADD kafka $GOPATH/src/github.com/opencord/voltha-go/kafka
-ADD afrouter $GOPATH/src/github.com/opencord/voltha-go/afrouter
-ADD vendor $GOPATH/src/github.com/opencord/voltha-go/vendor
-
-# Copy required proto files
-# ... VOLTHA proos
-# Repeat here even if it's done in the base
-ADD afrouter/arouter.json /src
-COPY vendor/github.com/opencord/voltha-protos/go/voltha.pb /src
-
-#
-# Copy generated executables here
 WORKDIR $GOPATH/src/github.com/opencord/voltha-go
 
-# Build rw_core
-RUN cd afrouter && go build -o /src/afrouter
+# Copy files
+COPY rw_core ./rw_core
+COPY afrouter ./afrouter
+
+# Copy config and runtime protobuf needed for routing
+RUN cp afrouter/arouter.json /build
+RUN cp vendor/github.com/opencord/voltha-protos/go/voltha.pb /build
+
+# Build
+RUN cd afrouter && go build -o /build/afrouter
+
 
 # -------------
 # Image creation stage
 
-FROM alpine:3.6
+FROM alpine:3.9
 
 # Set the working directory
 WORKDIR /app
 
 # Copy required files
-COPY --from=build-env /src/afrouter /app/
-COPY --from=build-env /src/arouter.json /app/
-COPY --from=build-env /src/voltha.pb /app/
-WORKDIR config
-WORKDIR /app
+COPY --from=build-env /build/afrouter /app/
+COPY --from=build-env /build/arouter.json /app/
+COPY --from=build-env /build/voltha.pb /app
 
-#CMD cd /app && ./arouter -config config/arouter.voltha2.json
-
-# Set the config volume
-
+ENTRYPOINT ["/app/afrouter"]