Draft: Handle password forms with dozens of invisible password elements

I developed this to fix my electric utility's login form, but this only fixes autofill. Saving is separately broken because the form gets deleted when you click the submit button, then a new form is created without any password entries, then that form gets submitted. They're really trying as hard as possible to thwart password managers. :/

Setting this in Draft state because (a) it's not actually enough to make the website https://www.ameren.com/missouri work properly, and (b) it's sufficiently scary that I'm not sure we should do it even if we can....