feat: use Raw Public Keys (RFC 7250) instead of self signed certificates

[dignifiedquire]

Once rustls/rustls#2062 has landed, we should start the integration to it.

[cpu]

FYI v0.23.16 was cut today with RPK support.

[dignifiedquire]

thanks for the update @cpu !

[dignifiedquire]

Current implementation plan:

Add support for this to iroh-net and iroh using an option

fn set_tls_authentication(auth: TlsAuthentication) { .. }

pub enum TlsAuthentication {
  // Current self signed certificates
  X509,
  // The new mechanism
  RawPublicKey,
}

• By default we will use X509, as changing is a protocol breaking change. But we should update our example code to encourage all new users, and those that control their full deployment to switch to RawPublicKey.
• In a couple of releases, we will deprecate X509 to make it clear to users that this will go a way.
• As a final step in our breaking release before 1.0 we will remove these methods again, and the ability to use the X509 variant.

[dignifiedquire]

It looks like there is some movement to support both on rustls: rustls/rustls#2258 this would be amazing as this would allow us to mgirate without a breaking network change