Add CI to build both images

Add CI to build both images

This change adds the needed directory structure and config
files under the ci directory to build both the mc-core and
the mc_listener images.  Changes are needed in the ci
management repo to "activate" these, so this is part 1
which sets the stage for the multi-image build.

Also added a brief README at the top level.

Signed-off-by: E. Scott Daniels <daniels@research.att.com>
Change-Id: Ief76d4e1a8811d06464af0d5d158de27bf5b0221

Make core directory name under ci consistent with root source dir

Change-Id: I797c0f6373dd12669a032e619a64dafc1322a401

Add correct tag for mc-core

Signed-off-by: E. Scott Daniels <daniels@research.att.com>
Change-Id: I0087ced6c876c3b91ca74f1b6e13a909ab765d4d

Add top level readme

Signed-off-by: E. Scott Daniels <daniels@research.att.com>
Change-Id: I0c1eb11d26ab86f0bda1a84256587bc2da460d53