Include base image configuration in the downloaded file name

CodersOS images can be built from a variaty of base images.
We may want to include infomration about the base image into the name of the iso.

Example: If we build from

    codersosimages/xubuntu-16.04.1-desktop-amd64

We should include `xubuntu-16.04.1-desktop-amd64` somewhere in the file name.