Update and minimize jquery-ui

So that it doesn't unnecessarily conflict with bootstrap's $.fn.button().

This is a jQuery UI custom download with just the components we currently
use:

* Version: 1.11.2
* Interactions
  * Sortable
* Theme: Cupertino

(Other dependencies get selected automatically.)
Remove jquery copy in jquery-ui

We get our jQuery elsewhere.
Copy disable-on-submit functionality over from frontend to dashboard
disable-on-submit all submit buttons: frontend
disable-on-submit all submit buttons: dashboard
disable-on-submit all submit buttons: sandbox
disable-on-submit all submit buttons: demo site