Account creation work in progress

Needs uaa endpoint to exist

[#73324702] https://www.pivotaltracker.com/story/show/73324702
Use the uaa endpoint to finish creating accounts

new account passwords are validated for non-zero length and password/password_confirmation field match

[#73324702] https://www.pivotaltracker.com/story/show/73324702
Update form error message box styling

[#73324702] https://www.pivotaltracker.com/story/show/73324702