Support disabling certificate checks for frequently rotated certificates

[bephinix]

Is your feature request related to a problem? Please describe.

We are currently using Hashicorp Vault with Cert-Manager to create, manage and rotate certificates which are used for the external ingress to our minio clusters.
Due to a policy, these certificates are only valid 7 days.
Unfortunately, it is not possible to disable the events created by the minio operator: Minio certificate 'my-minio-cert' is expiring in 6 days.
Therefore the operator will spam these events although this is intended behaviour.

Describe the solution you'd like

Either on operator-level or tenant-level there should be an option to disable these checks and/or to set a custom threshold (e.g. 1 day).

Describe alternatives you've considered

As it is currently hardcoded, there are no alternative solutions:

operator/pkg/controller/custom.go

Lines 109 to 121 in b7f6870

	if expiresInDays >= 10 && expiresInDays < 30 {
	c.RegisterEvent(ctx, tenant, corev1.EventTypeWarning, "CertificateExpiring", fmt.Sprintf("%s certificate '%s' is expiring in %d days", certType, secret.Name, expiresInDays))
	}
	if expiresInDays > 0 && expiresInDays < 10 {
	c.RegisterEvent(ctx, tenant, corev1.EventTypeWarning, "CertificateExpiryImminent", fmt.Sprintf("%s certificate '%s' is expiring in %d days", certType, secret.Name, expiresInDays))
	}
	if expiresInDays > 0 && expiresInDays < 1 {
	expiresInHuman = fmt.Sprintf("%v hours, %v minutes, and %v seconds", expiresInHours, expiresInMinutes, expiresInSeconds)
	}
	if expiresInDays <= 0 {
	c.RegisterEvent(ctx, tenant, corev1.EventTypeWarning, "CertificateExpired", fmt.Sprintf("%s certificate '%s' has expired", certType, secret.Name))
	expiresInHuman = "EXPIRED"
	}

Additional context

Hashicorp Vault recommends issuing short-lived certificates using their PKI mount:
https://developer.hashicorp.com/vault/tutorials/secrets-management/pki-engine
This works fine for other services, e.g. Traefik Ingress etc.

[cesnietor]

We'll consider adding a min and max expiration values. Minimum would be 1. @allanrogerr