Don't require CN for certs

[jefferai]

Now that we support some other parameters for generating certs we have requests to not require a CN/SAN be present in cert requests. If an admin wants to allow this I don't see a reason why it's strictly necessary.

We should probably add two toggles: one to control whether a CN is required, one to control whether a SAN is required. I'm iffy on the last one though, not sure if it's actually useful.

Adding to 0.9.3, may slip.