Port NodeInfo to ARM64

Signed-off-by: Alex Ellis <alexellis2@gmail.com>

sample-functions/NodeInfo/Dockerfile.arm64

+FROM arm64v8/alpine:3.6
+
+RUN apk --update add nodejs nodejs-npm
+
+ADD https://github.com/openfaas/faas/releases/download/0.6.5/fwatchdog-arm64 /usr/bin/fwatchdog
+RUN chmod +x /usr/bin/fwatchdog
+
+COPY package.json .
+COPY main.js .
+RUN npm i
+ENV fprocess="node main.js"
+CMD ["fwatchdog"]