This commit adds artwork to the NixOS 23.11 release featuring a Tapir.
The logo was taken from NixOS/nixos-artwork.
https://github.com/NixOS/nixos-artwork/blob/master/logo/nix-snowflake.svg
The image of the Tapir was taken by me at Zoo Berlin this morning, thus
there are no license complications.
I have cropped the picture and adjusted the colors.
