rework the updater

[prplwtf]

This PR (once finalized) will:

• rework the blueprint updater
  • allow for more easily implementing new changes before doing the actual update process
  • change how updates are fetched (branches so we can do fancy stuff with workflows before the update is actually fetched)
  • change the working directory for updates
• create a breaking change for the legacy updater
  • provide users with instructions when running the legacy updater

[Loki-101]

Looks good to me! Initial tests in the Docker environment show no breaking changes.