Add RSA key generation

[est31]

Uses the recently added RSA key generation support of aws-lc-rs.

Fixes #229

[djc]

Nice!

[cpu]

Thanks for picking this up!

I think this should come with at least one unit test to prevent regressions and to demonstrate the feature works as intended.

It also looks like we could probably drop the dev dependency on the rsa crate now? It's only used in the rsa-irc.rs example for key generation and I think it would be better to show Rcgen doing this natively. The rsa crate has an unresolved vulnerability that makes its removal from rcgen particularly tempting IMO.

[cpu]

One more thought: It would be ideal to also see rustls-cert-gen updated w/ RSA keygen support alongside this work:

rcgen/rustls-cert-gen/src/cert.rs

Lines 205 to 212 in 3c3e984

	/// Supported Keypair Algorithms
	#[derive(Clone, Copy, Debug, Default, Bpaf, PartialEq)]
	pub enum KeyPairAlgorithm {
	Ed25519,
	#[default]
	EcdsaP256,
	EcdsaP384,
	}

[est31]

Thanks for the reviews, will look into addressing them tomorrow.

[cpu]

Thanks 👍

Did you have thoughts on dropping the rsa dev-dep for the one example? I think it's fine to omit in this branch, just curious if you're interested in the idea generally for potential follow-up.

[cpu]

Should this enum variant maybe carry RsaKeySize now that the rcgen side supports specifying key size?

[est31]

Maybe, yeah, happy to see followup PRs for it.

[est31]

Did you have thoughts on dropping the rsa dev-dep for the one example?

Yeah we can drop it I think, but would prefer to do it in a followup.

[djc]

Nit: the _ prefix looks unidiomatic to me, but not sure I have a better idea.

[est31]

Yeah, not really perfect. r#2048 doesn't work, but I like _2048 more than Rsa2048.