new port mail/py-offlineimap3

From: Derek Schrock <dereks_at_lifeofadishwasher.com>
Date: Tue, 27 Dec 2022 00:12:57 UTC
Anyone able to commit mail/py-offlineimap3 and its depends.  I've been
using it locally for a while (connected to gmail) without issue.

mail/py-offlineimap3
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=262233

mail/py-rfc6555
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=262231

mail/py-imaplib2
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=262232