Push Logic to setup.rb

Based on feedback, here's an attempt to simplify the scripts a user is presented with when checking out this repo to run for the first time.

We adopt the assumption that the user is knowledgeable enough to yum install ruby prior to running, and in the case of RHEL knows to subscription-manager register --autosubscribe.

After this we push everything else into setup.rb.

This is an initial draft which should be pretty close to ready which basically does what the old bash scripts did, along with a few fixes.

After this I'm hoping to make the OS detection automatic rather than manual, and possibly handle setup of the devel user. (there are some complications with sudo if run as root)