Break out prepare step into a script

• Move the prepare step into its own separate script.
• Copy the before_script steps into their own two scripts: one for functions and one for setup
• Add unit testing for the prepare step

This opens the door for some big improvements:

• Testing proposed changes to scripts in the pipeline when we do CI (not happening right now)
• Moving bash out of the pipeline into smaller, testable scripts

Signed-off-by: Major Hayden major@redhat.com