Remove admin flair from admins' displayed names

[noah-schechter]

Current We display the word Admin next to admins' usernames.

Proposed We shouldn't display the word Admin next to admins' usernames because it looks like flair; this makes the conceptual distinction between instance-level roles like admin and flair like Staff blurry. We've seen this become an issue for GAP.

I also don't think there's much benefit from displaying the admin label.

@milesmcc If you agree, let me know in a comment but leave the implementation to me. I want to keep familiarizing myself with the codebase and tiny issues like these are perfect for that.