Create job to build dist of MR + unmanaged project

Luis has idea to make job parallel to autorelease (which will only build managed projects) that also adds some project, like an unmanaged project. This job could run all the time, like autorelease, to give feedback. It will give unmanaged projects feedback about their snapshot integration with managed projects. The job would just add the unmanaged project's snapshot artifact to the managed distro and serve up a resulting distro for projects to test. There would not be verifications on the RelMang side to take care of, it's up to the project to check if the resulting distro works.