Nagbar for maintenance window

[nostelux]

Problem

Right now there is no way to tell the users that there is going to be maintenance done and that the self-hosted instance may experience downtime.

Proposal

Having a setting for a nagbar in the admin panel would alert the users that maintenance is scheduled at... We've already seen this on the hosted Fluxer.app instance.

Notes

No response

Checks

• I searched existing discussions.

[midblep]

I think this should be extended to allowing admins to make any arbitrary nagbar for users, feels much more flexible and would cover any alternative usecases as well.