feat(wpcarro): Define deploy-diogenes helper

TL;DR:
- Mimmick depot's bin -> __dispatch.sh for personal utils
- Define deploy-diogenes to more tighten my feedback loop

Change-Id: I2b12a1c32a955574f5be5d4f38025bd97e9c7b77
Reviewed-on: https://cl.tvl.fyi/c/depot/+/4751
Tested-by: BuildkiteCI
Reviewed-by: wpcarro <wpcarro@gmail.com>
Autosubmit: wpcarro <wpcarro@gmail.com>

users/wpcarro/bin/__dispatch.sh

@@ -0,0 +1,24 @@
+#!/usr/bin/env bash
+# This script dispatches invocations transparently to programs instantiated from
+# Nix.
+#
+# To add a new tool, insert it into the case statement below by setting `attr`
+# to the key in nixpkgs which represents the program you want to run.
+set -ueo pipefail
+
+TARGET_TOOL=$(basename "$0")
+
+case "${TARGET_TOOL}" in
+  deploy-diogenes)
+    attr="users.wpcarro.nixos.deploy-diogenes"
+    ;;
+  *)
+    echo "The tool '${TARGET_TOOL}' is currently not installed in this repository."
+    exit 1
+    ;;
+esac
+
+result=$(nix-build --no-out-link --attr "${attr}" "${REPO_ROOT}")
+PATH="${result}/bin:$PATH"
+
+exec "${TARGET_TOOL}" "${@}"