WIP: Dev root dockerfiles

[crkrenn]

@patcon & @metasoarous,

I'm finally back in the saddle again working on node-convict config, but I have some catching up to do because of all the commits you've made lately.

One incremental step that would be helpful would be for you to consider this pull request. It

1. adds a Makefile,
2. adds a "headless" target to e2e, and
3. moves the docker build directories up one level as @patcon suggested earlier. This will make the config process much less messy because all docker builds will be able to access the config directory.

I know that this is (somewhat?) bad form, and I can split this pull request into three if you would like.

-Chris