self-generated secret for webhook does not seem to generate a compliant tls secret

[raffaelespazzoli]

self-generated webhook secrets do not seem to follow the standard rules for tls secrets. Which to my undertsanding are:

1. the secret must be of type kubernetes.io/tls
2. the keys should be tls.key, tls.crt, ca.crt. ca.crt should contain the entire ca_bundle, so there should not be a need for a fourth file.
   From what I see the code does not set the type of the secret and generates the followinf keys:

const (
	// CAKeyName is the name of the CA private key
	CAKeyName = "ca-key.pem"
	// CACertName is the name of the CA certificate
	CACertName = "ca-cert.pem"
	// ServerKeyName is the name of the server private key
	ServerKeyName = "key.pem"
	// ServerCertName is the name of the serving certificate
	ServerCertName = "cert.pem"
)

Which I guess are the files expected by the code.
This limits interoperability with other mechanism of generating secrets.

[DirectXMan12]

we've removed self-generating certificates in v0.2.0, so this is less of an issue (and changing it might be a breaking change). I'm going to close this, but if you have an argument for why it wouldn't be a breaking change to the 0.1.x branch, I'd be happy to review a PR there.