Build the swarm

Moves UpdateSharedValidatorsTask to validators.rs. While prior planned to
re-use a validators object across connecting and peer state management, the
current plan is to use an independent validators object for each to minimize
any contention. They should be built infrequently enough, and cheap enough to
update in the majority case (due to quickly checking if an update is needed),
that this is fine.

coordinator/src/p2p/authenticate.rs

@@ -23,10 +23,11 @@ use crate::p2p::{validators::Validators, peer_id_from_public};
 
 const PROTOCOL: &str = "/serai/coordinator/validators";
 
-struct OnlyValidators {
-  validators: Arc<RwLock<Validators>>,
-  serai_key: Zeroizing<Keypair>,
-  noise_keypair: identity::Keypair,
+#[derive(Clone)]
+pub(crate) struct OnlyValidators {
+  pub(crate) validators: Arc<RwLock<Validators>>,
+  pub(crate) serai_key: Zeroizing<Keypair>,
+  pub(crate) noise_keypair: identity::Keypair,
 }
 
 impl OnlyValidators {