[Feature Request]: Allow disable SMTP certificate verification #3166

Describe the feature you'd like

I didn't find any way to use SMTP server with self signed certificate.

It would be great to have an option like 'MAIL_TLS_VERIFICATION=true/false'

To allow insecure certs we need only add folowing to app/Config/mail.php

'stream' => [
   'ssl' => [
       'allow_self_signed' => true,
       'verify_peer' => false,
       'verify_peer_name' => false,
   ],
],

Describe the benefits this feature would bring to BookStack users

Sometimes users need to use self signed certificates and usually services allow to disable TLS verification, but not bookstack.

Additional context

No response