Replace manuals accordion with gem accordion

[owenatgov]

What

Replace the custom manuals accordion (collapsible collection) with the components gem accordion. This includes:

• Moving the processing of the markup for individual manuals from the js to the document model
• Updating the updates view
• Removing evidence of the previous accordion implementation. This includes all of jasmine as there are now no js modules within this repo to test and therefore no point in including the test suite

Why

This is part of work within the govuk accessibility team to ensure that accordions are consistent across gov.uk. Manuals frontend has been using a bespoke accordion implementation which bolts on accordion functionality on top of govspeak content from manuals publisher. This creates risk because any updates to our accordion can't reliably permeate to manuals and could create hidden legacy code and accessibility issues. This change creates a relationship between manuals and our components gem, as is the case with our other frontend apps, to minimise risk and increase consistency between manuals and the rest of gov.uk.

The team are conscious that this is, in a sense, perpetuating the hack and the ideal would be to change the publishing workflow to account for accordion content, thus mitigating the need for any sort of preprocessing of the content item. We don't have the resource or knowledge in the team to action this, however an issue has been raised addressing this need.

Card

Pages tested against

• Manuals page
• Manuals page with advanced accordion markup
• HMRC manuals page that doesn't use accordions but still relies on the same document model as those using accordions to render content
• Manual updates page

Visual changes

Before

After

[owenatgov]

Note on tests

End to end test are currently failing. This is because this PR introduced a test failure in the publishing-e2e-tests repo due to the significant change in markup. I've created a separate PR to handle this. As per the e2e contribution guidance, once this has been reviewed and approved I'll set this branch to test against my e2e branch, merge my changes, deploy and then merge my e2e PR.

[ChrisBAshton]

LGTM - but made some code quality suggestions below.

I'd also amend the last commit to include the context you provided on Slack around why you're removing Jasmine 👍

[ChrisBAshton]

LGTM 👍 thanks for making the changes! One or two non-blocking comments below: