Expiration date and more variables in notification emails

[McLaynV]

Is your feature request related to a problem? Please describe.
When I receive a notification email about certificate expiration, I want to know

• what expires (subject, issuer, serial number)
• when it expires (expiration date)

I tried adding Expiration: ${notificationData.expiresAt} in the notification email template, but it didn't work.

Describe the solution you'd like
At least add expiresAt to the variables that can be used in notification emails.

However, allowing all properties and attributes would be a more generic solution for similar use cases.

Describe alternatives you've considered

Additional context