Add a LibP2P instantiation to coordinator

It's largely unoptimized, and not yet exclusive to validators, yet has basic
sanity (using message content for ID instead of sender + index).

Fixes bugs as found. Notably, we used a time in milliseconds where the
Tributary expected  seconds.

Also has Tributary::new jump to the presumed round number. This reduces slashes
when starting new chains (whose times will be before the current time) and was
the only way I was able to observe successful confirmations given current
surrounding infrastructure.

coordinator/tributary/src/lib.rs

@@ -103,6 +103,8 @@ impl<D: Db, T: Transaction, P: P2p> Tributary<D, T, P> {
     validators: Vec<(<Ristretto as Ciphersuite>::G, u64)>,
     p2p: P,
   ) -> Option<Self> {
+    log::info!("new Tributary with genesis {}", hex::encode(genesis));
+
     let validators_vec = validators.iter().map(|validator| validator.0).collect::<Vec<_>>();
 
     let signer = Arc::new(Signer::new(genesis, key));