Add collections to publisher metadata if B variant

[andrewgarner]

https://trello.com/c/kcZ8VQS7

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Visual regression results:
https://government-frontend-pr-1049.surge.sh/gallery.html

Component guide for this PR:
https://government-frontend-pr-1049.herokuapp.com/component-guide

[vanitabarrett]

This might be a design question: do we want "and 2 others" as well as "+ show all"? I think previously we've combined the two, so "+ 2 others" (for example) becomes the toggle link.

[andrewgarner]

When I looked at this with Alan for the top banner we had a couple of assumption that led to this approach:

1. the "+" or "-" suggests that the link will show or hide and not take you to another page which may deter interaction.
2. "and X others" for a hyperlink that hides an element on the page doesn't describe the behaviour.

[vanitabarrett]

These should probably be translated strings

[andrewgarner]

@vanitabarrett I've added translation support with 3a01e37 but we don't have actual translations.

[vanitabarrett]

@andrewgarner As this is a change to the publisher metadata component, we probably need to add a test in publisher_metadata_spec.rband an example in the component yml docs (as adding a collection has specific behaviour, especially when there are more than 2)