Apply standard GOV.UK breadcrumb styling

Makes sense for the breadcrumbs to be consistent with the existing GOV.UK style
Change ALPHA label to BETA

Because for manuals published on GOV.UK, the content is accurate and complete.
Merge pull request #101 from alphagov/change-alpha-to-beta

Change ALPHA label to BETA
Merge pull request #100 from alphagov/breadcrumb-styling

Apply standard GOV.UK breadcrumb styling