feat: Add nix in tools.d

tools.d/nix.bash

@@ -0,0 +1,15 @@
+#!/bin/bash
+
+# Install nix (with the nix-installer tool from DeterminateSystems)
+# (See https://github.com/DeterminateSystems/nix-installer)
+
+if ( ! command -v nix &> /dev/null ); then
+  curl --proto '=https' --tlsv1.2 -sSf -L https://install.determinate.systems/nix | sh -s -- install
+fi
+
+# Install home-manager
+if (command -v nix-channel && command -v nix-shell &> /dev/null ); then
+  nix-channel --add https://github.com/nix-community/home-manager/archive/release-24.05.tar.gz home-manager
+  nix-channel --update
+  nix-shell '<home-manager>' -A install
+fi