Add script to build a Jenkins Master
Add script to build a Jenkins Master

Adding a new script that can be used to deploy a jenkins master for now
only using Docker, and in the future adding support to deploy the
created image to a kubernetes cluster.

Basic Concept of the Script:
start
Clean the Workspace of files that would be leftover if reusing directory
Create the Dockerfile, based it on the template found here:
  https://github.com/jenkinsci/docker/blob/master/Dockerfile
Clone in the jenkinsci/docker repo
Copy the scripts that are expected by the Dockerfile into the workspace
Generate the plugins.txt, a list of plugins to install at startup
Build the image
Launch into Docker:
  Check if running as root:
    yes:
      Chown Directories to be owned by the jenkins user
    no:
      Verify mounted directories are owned by the jenkins user:
        yes:
          continue as the jenkins user will be able to access freely
        no:
          fail as this will cause permission errors
  Run the docker container
finish

Change-Id: Ib3492039b2d12b0d07909cd9f3e681993d7d7bc3
Signed-off-by: Alanny Lopez <e14acacdad65705f1f3eabff55e179ec2ff1cb1d@ibm.com>

openbmc/openbmc-build-scripts,openbmc/openbmc-build-scripts