Add SMTPS notify

[popexie]

Description

Checklist

• I have reviewed the contributing guidelines.
• I have included unit tests for my changes or additions.
• I have successfully run make test-docker with my changes.
• I have manually tested all relevant modes of the change in this PR.
• I have updated the documentation.
• I have updated the changelog.

Questions or Comments

[jertel]

Thanks for your contribution. I don't think this is needed any longer. Did you see the new feature that was added a few weeks ago? It allows any of the built-in alerters to be used for notifications. That then allows the ability to send emails over SMTPS/TLS/etc.

[popexie]

This patch is not for rule notification. This is for sending notification of ElastAlert2 itself.

[jertel]

The change I mentioned earlier is not for rule notification. It's for system error notifications. Please see the latest CHANGELOG.md.

[popexie]

Please check function send_notification_email in elastalert.py. It does not support SMTPS.

[jertel]