Configure ports used for shipyard/lb and shipyard/shipyard using environment variables

In this pull request I'm offering changes to permit overriding the assumed ports 80 and 8000 for the shipyard/lb and shipyard/shipyard containers.  This will only work if those images are also updated to use matching ports.  

I presume this this commit fixes #1 or at least in part, along with parameters/environment variables for the other projects. I am willing to work on those changes in separate pull requests as well (for those projects).