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/assets/javascripts/main.js

@@ -2,7 +2,7 @@ $(() => $("time.timeago").timeago());
 
 $(() => GOVUK.modules.start());
 
-$(() => new GOVUK.SelectionButtons('.block-label input, .sms-message-option input'));
+$(() => new GOVUK.SelectionButtons('.block-label input'));
 
 $(() => $('.error-message').eq(0).parent('label').next('input').trigger('focus'));