When showing username and organization together, hide individual org names

[allanlasser]

Feedback from @morisy:

In the document view, documents that are associated with a user's org instead of another org currently use the attribution field in the bottom right to go something like "Michael Morisy (morisy)" with their username being in the organization field. If it's uploaded by an individual and not attached to a non-individual organization, it should just list their name, not the org (or in this case, username) associated with their individual account. Example here: https://next.www.documentcloud.org/documents/25330349-opposition-to-motion-to-dismiss/

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I can think of two places where we're rendering user names in this way: in the DocumentMetadata and in the DocumentListItem.

Unrelated to UI presentation, we should be collapsing user accounts into individual org "profiles", and relying on the individual org for things that we're calling "Yours". This is partly a Squarelet issue, since you can't edit individual org details now, and partly a DocumentCloud backend issue, since we should have documents associated with individual orgs (if we aren't already).

[allanlasser]

We also have this logic in DocumentEmbed:

  $: contributedBy = settings.onlyshoworg ? org : `${user} (${org})`;

And this in api/document:

function userOrgString(document: Document): string

All this can be reconciled by a Contributor component:

<DocumentContributor document:Document orgOnly:boolean />