Alert when certificates expired

[Tembhum]

Is your feature request related to a problem? Please describe. Users are not able to push/pull images due to certificates expiry as there is no alerts when the certificate expired

Describe the solution you'd like Users would like to have an automatic certificate rotation and certificate expiration alert feature.

Describe the main design/architecture of your solution A warning and alert or certificate expiring date on Harbor UI could be a possible solution

[github-actions[bot]]

This issue is being marked stale due to a period of inactivity. If this issue is still relevant, please comment or remove the stale label. Otherwise, this issue will close in 30 days.

[stonezdj]

Because the certificate might be configured in LB or Ingress, Harbor core can't check if its certificate expires internally, there is no good solution for it.