Ability to monitor cert expirations

[vivek-koppuru]

What would you like to be added:

Look into how to expose functionality or tooling to show when certs are expiring and build alarms around out.

Why is this needed:

Currently the only way to check if certs are going to expire are through this manual approach: https://anywhere.eks.amazonaws.com/docs/clustermgmt/security/manually-renew-certs/#:~:text=Commands%20below%20can%20be%20used%20for%20quickly%20checking%20your%20certificates%20expiring%20date%3A

There external solutions here not recommended by AWS but an option to see if we can validate and put a recommendation in our documentation: https://grafana.com/blog/2020/03/04/pro-tip-how-to-monitor-client-certificate-expirations-with-prometheus/