add tutorial setup script to share/spack (#17705)

* add tutorial setup script to share/spack

* Add check for Ubuntu 18, fix xvda check, fix apt-get errors
  - now works on t2.micro, t2.small, and m instances
  - apt-get needs retries around it to work

Co-authored-by: Todd Gamblin <tgamblin@llnl.gov>