Slash upon Tendermint evidence

Decoding slash evidence requires specifying the instantiated generic
`TendermintNetwork`. While irrelevant, that generic includes a type satisfying
`tributary::P2p`. It was only possible to route now that we've redone the P2P
API.

coordinator/src/main.rs

@@ -1,7 +1,7 @@
 mod tributary;
 
 mod p2p {
-  use serai_coordinator_p2p::*;
+  pub use serai_coordinator_p2p::*;
   pub use serai_coordinator_libp2p_p2p::Libp2p;
 }