Add checkbox to disable SSL peer verification for SMTP notifications
Some mail servers do not use a certificate that can be validated by the current code (e.g. custom self-signed CA or cert), but they can still benefit from TLS if the user opts to not validate the cert.
The current Pear Mail and Net_SMTP code supports this now, but we need a GUI knob and some backend code to enable it.
Should be simple, one checkbox that sets the right socket option. A user has already confirmed the backend change works, but it needs to be made conditional.
See the attached patch for the part that needs added to disable TLS verification, and see https://forum.netgate.com/topic/136299/pfsense-2-4-4-smtp-question/5 for more discussion.