New reset password form

This is an attempt to finish @dukex's work in #4250.

I have fixed the problems that were failing the tests, and have fixed the styling issues with help from @svbergerem.

The one thing remaining is to get it to redirect to /stream on submission of the form. My best guess is I need to make a change to ````/app/views/devise/shared/_links.haml```` in order to achieve this. But I'm defeated by the syntax so far. If anyone can give me some guidance, I'd be grateful.