Show admin lozenges on workspace members page (so I know who to contact) (BB-11066)

I had an issue recently where none of the current committers to a fairly major Atlassian repo were admins. I thus had to seek Bitbucket support in order to find out who the admins were to contact.

It's possibly an edge case, and is probably in this situation from being a very old repo before the current default auth settings were in place.

Nonetheless it seems reasonable in general for the admins of a repo to be displayed somewhere.