mail: expose 465 for mail submission

Port 465 is implicit TLS. rfc8314 is now pushing this as a standard
and some mail clients like outlook have already taken this to heart.

Note that this port is sometimes confused with SMTPS. Unlike SMTPS,
this is being used for "submissions" (by a client) as opposed to
server transfer protocol.

This is more secure than port 587+STARTTLS. We reject credentials
on insecure connections but it's too late.

See also:

https://www.fastmail.help/hc/en-us/articles/360058753834
https://www.agwa.name/blog/post/starttls_considered_harmful
https://linuxguideandhints.com/misc/port465.html

src/mail.js

@@ -692,7 +692,7 @@ async function configureMail(mailFqdn, mailDomain, serviceConfig) {
 
     const allowInbound = await createMailConfig(mailFqdn, mailDomain);
 
-    const ports = allowInbound ? '-p 587:2587 -p 993:9993 -p 4190:4190 -p 25:2587' : '';
+    const ports = allowInbound ? '-p 587:2587 -p 993:9993 -p 4190:4190 -p 25:2587 -p 465:2465' : '';
 
     const cmd = `docker run --restart=always -d --name="mail" \
                 --net cloudron \