Tools: Add Devbox+DirEnv integration to simplify build tool setup (#11406)

Co-authored-by: Laurent Cozic <laurent22@users.noreply.github.com>

.envrc

@@ -0,0 +1,9 @@
+#!/bin/bash
+
+# Automatically sets up your devbox environment whenever you cd into this
+# directory via our direnv integration:
+
+eval "$(devbox generate direnv --print-envrc)"
+
+# check out https://www.jetpack.io/devbox/docs/ide_configuration/direnv/
+# for more details