demo CI/CD pipeline with gitlab

[ketzacoatl]

• Use the gitlab demo env from the test/demos suite in the module repo
• Setup a git repo with the .gitlab-ci.yml spec to run a bunch of CI/CD demos
• Demo multiple CD / update strategies and scenarios
• Use gitlab's "manual" param for the build, for some of the CD demos (to give the operator the opportunity to test)
• WRT nomad, see docs on:
  • rolling upgrades - https://www.nomadproject.io/docs/operating-a-job/update-strategies/rolling-upgrades.html
  • A/B and canary deployments - https://www.nomadproject.io/docs/operating-a-job/update-strategies/blue-green-and-canary-deployments.html
• Run gitlab in a corporate account, connect to the compute cluster in a non-corporate account
• docs on signals - https://www.nomadproject.io/docs/operating-a-job/update-strategies/handling-signals.html