Prototype to jQuery Changes

## Changes Made
- Added jQuery, jQuery UI and jQuery DataTable files
- Change MarkUs login page to use jQuery
- Change Dialog boxes to use jQuery
- Change user role switch to use jQuery
- Change auto update for submissions collected in the assignments dashboard
- Removed a handful of RJS files and replaced with jQuery equivalents
- Made minimal changes to backend to support jQuery AJAX calls
- Added jQuery browser detection

## Future changes now made possible
- Can switch over from Prototype FilterTable to jQuery DataTables for rendering tables
- Can switch over more dialog boxes to use jQuery and jQuery UI for wider browser support
- Can complete a full migration from Prototype to jQuery before upgrading to a Rails version where jQuery becomes the default.