feat: add one line quickstart

[drbh]

This PR adds a simple quickstart file that conditionally installs docker and nvidia-container-toolkit before fetching the TGI docker container and running it with HuggingFaceH4/zephyr-7b-beta

It can be run with

bash quickstart.sh

additional TGI can be installed without cloning the repo

# using this branch
curl --proto '=https' --tlsv1.2 -sSf \
    https://raw.githubusercontent.com/huggingface/text-generation-inference/add-quickstart-script/quickstart.sh \
    | bash

# if merged
curl --proto '=https' --tlsv1.2 -sSf \
    https://raw.githubusercontent.com/huggingface/text-generation-inference/quickstart.sh \
    | bash

[Narsil]

Not nearly enough to support all the linux variants I'm afraid :)

[Narsil]

I don't think we should go that route, I feel like the pip install thing is more what some users might desire, not necessarily 1 liner to run docker (which is going to be annoying to maintain anyway)