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

gulpfile.babel.js

@@ -54,7 +54,6 @@ gulp.task('copy:govuk_template:images', () => gulp.src(paths.template + 'assets/
 gulp.task('javascripts', () => gulp
   .src([
     paths.toolkit + 'javascripts/govuk/modules.js',
-    paths.toolkit + 'javascripts/govuk/selection-buttons.js',
     paths.src + 'javascripts/detailsPolyfill.js',
     paths.src + 'javascripts/apiKey.js',
     paths.src + 'javascripts/autofocus.js',