SSL certificate expiration metric

[obrienrobert]

Is your feature request related to a problem? Please describe.
The checkly_check_status metric provides the status of the core check, i.e the check either passes or fails. We have no metric that tells us if the SSL certificate expiration check has failed, i.e a certificate is going to expire in X number of days.

It would be great if information was exposed as a metric. This would allow the creation of create custom alerts and dashboards etc. to display a list of certificates and if possible, also their expiry date.

Describe the solution you'd like
Metrics that tell me if an SSL certificate check failed and also the certificates expiry date.

Additional context
Original request: https://checklycommunity.slack.com/archives/C04349E26EN/p1683124146213909