Create customer demo video for dhall direction

Created by: ggilmore

• Create fake fork of deploy-sourcegraph a with a few customizations (think CPU / RAM, additional environment variables maybe 3-4 in total): https://github.com/ggilmore/deploy-sourcegraph-demo/pull/1
• Show migration process involving ds-to-dhall
  • involves using https://github.com/sourcegraph/deploy-sourcegraph-dhall-archived and doing to the work to get the output to match ds-to-dhall’s and updating that old repository with any changes in the services
  • Show incremental diffing process that drives the with statements to copy and paste: https://github.com/ggilmore/deploy-sourcegraph-dhall-demo/blob/demo/video/generate.dhall and https://github.com/ggilmore/deploy-sourcegraph-dhall-demo/blob/demo/video/upstream.dhall
    • we can create a fake “docs” page that is just a text file to copy and paste from https://www.notion.so/ggilmore/dhall-documentation-99257b80625f4c3ba1964f96dd7b9902
• [ ] Show pipeline generating kubernetes yaml, and it being applied to a real cluster and working
  • not necessary, but we might as well since the prototype already creates real yaml
  • Decided that this part as not necessary since it would lengthen the video
• Show upgrade process
  • Need to do the work to modify https://github.com/sourcegraph/deploy-sourcegraph-dhall-archived with a branch with updated images: https://github.com/ggilmore/deploy-sourcegraph-dhall-demo/blob/demo/video/generate-upgrade.dhall