Move Nix files into a nix directory

Move everything from `config` to the root level.

nix/lib/shared/scripts/deliver.nix

@@ -0,0 +1,25 @@
+{ pkgs }:
+{
+  name = "deliver";
+
+  runtimeInputs = with pkgs; [ docker ];
+
+  text = ''
+    set +o pipefail
+
+    # Based on https://github.com/jessarcher/dotfiles/blob/ef692c35d64db2c13674dfc850a23b6acf9e8f91/scripts/deliver.
+
+    docker_compose_service_name=$(docker compose ps --services 2>/dev/null | grep '^app\|php$' | head -n1)
+
+    if [[ "$docker_compose_service_name" != "" ]]; then
+      if [ -t 1 ]; then
+        "${pkgs.docker}/bin/docker" compose exec "$docker_compose_service_name" "$@"
+      else
+        # The command is not being run in a TTY
+        "${pkgs.docker}/bin/docker" compose exec -T "$docker_compose_service_name" "$@"
+      fi
+    else
+      "$@"
+    fi
+  '';
+}