Add support for starttls on roundup-tracker.org

[rouilj]

Currently roundup-tracker.org users use email heavily. Due to a recent personal issue, I have had to move
to gmail as my email client.

I am unable to send email to issues@roundup-tracker.org because gmail wants to use starttls to send it over
a secure channel (probably port 25 since 587 isn't in use on the server). I get the following error from gmail:

The response from the remote server was:

454 4.7.0 TLS not available due to local problem 

in a delivery status notification (delay) from the gmail mail daemon.

It looks like this error is addressed in: https://www.24x7serversecurity.com/blog/unable-to-send-mail-using-postfix-starttls-authentication-4-7-0-tls-not-available-due-to-local-problem/

Would it be possible to enable startls so gmail users can correspond with roundup?

For testing, trying to open a ticket using gmail should work. You will get a delay message in 4 or so hours
on gmail if it can't establish a TLS connection.

Thanks.

-- rouilj

[JacobCoffee]

Hi @rouilj, starting to work on this this week.

[rouilj]

Hi Jacob:

I though we solved this. I could have sworn that email was getting through.
But I am having the same issue again and it looks like the PR was never merged.

-- rouilj