Make radio select work w/ new checkboxes/radios

The visual appearance of radio and checkbox form inputs changed in
GOV.UK Elements here:

https://github.com/alphagov/govuk_elements/pull/296

This was subsequently reimplemented with different markup and no
Javascript here:
https://github.com/alphagov/govuk_elements/pull/406

This has meant making the following changes to our app:
- changing the markup in our radio/checkbox macros to match the example
  markup given by GOV.UK Elements
- removing the previous Javascript file because it’s no longer needed to
  make the radios appear visual selected
- making the buttons on the scheduled job picker look like links,
  because the grey button style looked weird with the new radio buttons

app/templates/views/manage-users/permissions.html

@@ -4,9 +4,9 @@
   <legend class="form-label">
     Permissions
   </legend>
-  {{ checkbox(form.send_messages, block=True) }}
-  {{ checkbox(form.manage_service, block=True) }}
-  {{ checkbox(form.manage_api_keys, block=True) }}
+  {{ checkbox(form.send_messages) }}
+  {{ checkbox(form.manage_service) }}
+  {{ checkbox(form.manage_api_keys) }}
 </fieldset>
 
 <div class="form-group">
@@ -18,4 +18,4 @@
     <li>history of sent messages</li>
     <li>who the other team members are</li>
   </ul>
-</div>
+</div>