Sam Simpson

Updates the Dockerfile to use the new [GOV.UK Ruby base images](https://github.com/alphagov/govuk-ruby-images). Also updates the .ruby-version file to not specify a patch version, to allow for easier Ruby patching. Context: https://trello.com/c/Zy0fd25w/970-use-base-builder-images-in-all-the-app-dockerfiles

Move all of the still in-use resources out of govuk-aws and into this repository so everything is managed in one place by Terraform Cloud ```[tasklist] ### Remaining projects - [x]...

SSO on TFC technically works (we can log in with Google), but it isn't assigning teams properly, so we have to manually add people to the correct teams so they...