`substituteAll` supports templating with @variables@, which I think really cleans things up. Change-Id: Icfad15ac9e174495ba02260d817f7330f1616c6f Reviewed-on: https://cl.tvl.fyi/c/depot/+/4722 Reviewed-by: wpcarro <wpcarro@gmail.com> Autosubmit: wpcarro <wpcarro@gmail.com> Tested-by: BuildkiteCI