This is to configure the pipelines in buildkite.

To upload them, run =nix run .#ops.buildkite.upload=.

The state is stored in a GCS bucket (and it needs to be created before we run this).

The service account =terraform= needs to exist first, running =gcloud iam service-accounts list= will list them and we can verify it is defined. I might need to run =gcloud auth application-default login= in order to authenticate first.