Make service CA secret key parameters configurable

[simu]

Allow operators to customize the secret key parameters for the service CA. Currently the parameters are hard-coded.

k8s-service-ca-controller/certs/ca.go

Lines 128 to 132 in 2aa9526

	// TODO: make the private key config configurable?
	PrivateKey: &cmapi.CertificatePrivateKey{
	Algorithm: cmapi.ECDSAKeyAlgorithm,
	Size: 521,
	},