Updating https://www.freebsd.org/administration

From: Kurt Jaeger <pi_at_freebsd.org>
Date: Tue, 03 Oct 2023 09:44:13 UTC

I have this update for the webpage, see attached diff.
The list of postmasters is taken from the email alias postmaster@.

Would you prefer it as PR on bugs.freebsd.org or as review
on reviews.freebsd.org or can I just commit this update ?

pi@FreeBSD.org         +49 171 3101372                  Now what ?