GitLab

* nix: experimental support for building a Docker image

Run using something like:

```
docker run \
  --device nvidia.com/gpu=all \
  -it --rm -p 8080:80 \
  -v $PWD/data:/data \
  -v $PWD/tmp:/tmp \
  tgi-docker:latest \
  --model-id <model_id>
```

* Example of building the Docker image using Nix inside Docker

* Stream to make the builder image smaller

This avoids storing a Docker image tarball in the image. Instead,
stream the layers while doing `docker run`.

* Don't spam journalctl on Linux

* Other dockerfile.

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Co-authored-by: Nicolas Patry <patry.nicolas@protonmail.com>