Remove tokio dependency from serai-coordinator-p2p

Re-implements tokio::mpsc::oneshot with a thin wrapper around async-channel.

Also replaces futures-util with futures-lite.

coordinator/p2p/libp2p/src/lib.rs

@@ -19,7 +19,7 @@ use serai_client::{
   Serai,
 };
 
-use tokio::sync::{mpsc, oneshot, Mutex, RwLock};
+use tokio::sync::{mpsc, Mutex, RwLock};
 
 use serai_task::{Task, ContinuallyRan};
 
@@ -35,7 +35,7 @@ use libp2p::{
   SwarmBuilder,
 };
 
-use serai_coordinator_p2p::{Heartbeat, TributaryBlockWithCommit};
+use serai_coordinator_p2p::{oneshot, Heartbeat, TributaryBlockWithCommit};
 
 /// A struct to sync the validators from the Serai node in order to keep track of them.
 mod validators;