Here's an explanation for a lot of the confusion and the vagueness surrounding this. The draft scriptdraft script refers to the person who placed the order as "Sido-Dyas", which is a twist on Sidious (Palpatine) and the story line strongly indicated the role of the Sith in both impersonating the Jedi and placing the order for the army. I couldn't verify the authenticity of this draft, but assuming it is true and moving forward: