Isolate NodeJS and WCT Docker layers

Extract the setup of NodeJS and WCT from the main OS
image build, so that upgrading NodeJS and/or WCT would
not imply the rebuild of the base OS image.

Change-Id: Ifcd568987e5c0f0b4716ba76c3e44023c9a802ac
7 files changed
tree: df1007fbe4f759f508e0617cf29df5cbe4441157
  1. jenkins/
  2. jenkins-docker/
  3. worker/
  4. .gitignore