add Bash.gitlab-ci.yml

Add super simple Bash demo that just echos out some basic details. Good for people just getting started with CI that want to see something that works right out of the box. Working version running at https://gitlab.com/bbodenmiller/bash-ci-demo.

Good start, maybe later we should add artifacts to pass a file between the stages. But for a first iteraton, really good. Thanks! :)

merged