The nix image isn't used because it doesn't work, and we haven't been
updating our "pre-nix" tag since the changes were made. Reverts back to
being a regular Dockerfile.
* Add Docker image
* Try building the container in CI
* Uncomment testing lines
* Trim image step
* Hit 'em with a Docker load
* Oopsie!
* Add a tag and push!
* Fix image name 🤦
* Fix sudo
* Fix target name
* Build and push
* Fix login to docker hub
* Revert to Docker push
* Fix PATH
* Fix SHA
* Fix ca certs
* Fix ca certs
* Fix coping files in
* Fix docker init
* Fix Docker group and init
* Add comments to our Nix
* Fix build stage
* Add some more comments
* Remove old dogfood image files
* Tag and push with branch name
* Fix tag passing
* Fix tag passing
* Remove old pull triggers
* Convert gen to use Nix
* Add protobuf to the flake
* Add prettier to the dev shell
* Swap to the faster Nix cache action
* Add the correct yq
* Fix gen
* Add make to the flake
* Update extensions