Associate multiple need ids to an artefact

https://www.pivotaltracker.com/story/show/67206140

As a content designer,
I want to associate multiple needs in Maslow with a single item of content that meets those needs,
so I can show how needs are met on GOV.UK.

it also includes a big clean-up of code needed to display information about a need related to the artefact on the artefact edit page. product owners think this is not very useful, and editors can click on need ids and take a look at the need instead.