feat(server): Option to configure SMTPS transport (#22833)

* feat(server): Option to configure SMTPS transport

This commit adds a boolean option in the SMTP transport configuration to
enable the so-called "secure" mode. What it does is use SMTP over TLS
instead of relying on the more common STARTTLS option over plain SMTP.

* Add missing field in dto

* Add missing field

* Use a switch instead of text field

* Add field in spec

* chore: regen open-api

---------

Co-authored-by: Jason Rasmussen <jason@rasm.me>

server/src/services/notification-admin.service.spec.ts

@@ -14,6 +14,7 @@ const smtpTransport = Object.freeze<SystemConfig>({
         ignoreCert: false,
         host: 'localhost',
         port: 587,
+        secure: false,
         username: 'test',
         password: 'test',
       },