Multiple Dockerfile Builds per Project

Multiple Dockerfile Builds per Project

Instead of defining docker build jobs in terms of projects, we define
them in terms of dockerrepos. Each dockerrepo is associated with a
specific project and may have a seperate Dockerfile (which defaults to
'Dockerfile' if unspecified), and location for files needed by the
Dockerfile (default: 'docker').

This should allow for running multiple docker builds out of a single
project repository without having to modify the current docker build
scripts.

The output of this job configuration should match what is currently in
Jenkins.

Change-Id: I9089d57a0c7cc56be4225b56e96bec56be258f1f
Signed-off-by: Trevor Bramwell <tbramwell@linuxfoundation.org>