Is your feature request related to a problem? Please describe.
I would like to start using Fediseer - a chain of trust system for combatting spam and mailcious instances; to claim my instance and manage it, it requires admin's username to be exposed by API/Nodeinfo for verification purposes.
See relevant issue Fediseer/fediseer#77

Describe the solution you'd like
I'd like to have Mbin expose admin user/users in a relevant API endpoint, possibly /api/info or even /api/instance. It would be useful for general moderation/safety as well.

Describe alternatives you've considered
Fediseer's developer mentions putting it into Nodeinfo (Fediseer/fediseer#77 (comment)), yet I don't see it in the Nodeinfo schema, so not sure about it

Additional context
I seems like Mastodon API serves admin user as a part of contact info (at /api/v2/instance)
Lemmy does serve it as well (/api/v4/site)