Validator DHT (#494)

* Route validators for any active set through sc-authority-discovery

Additionally adds an RPC route to retrieve their P2P addresses.

* Have the coordinator get peers from substrate

* Have the RPC return one address, not up to 3

Prevents the coordinator from believing it has 3 peers when it has one.

* Add missing feature to serai-client

* Correct network argument in serai-client for p2p_validators call

* Add a test in serai-client to check DHT population with a much quicker failure than the coordinator tests

* Update to latest Substrate

Removes distinguishing BABE/AuthorityDiscovery keys which causes
sc_authority_discovery to populate as desired.

* Update to a properly tagged substrate commit

* Add all dialed to peers to GossipSub

* cargo fmt

* Reduce common code in serai-coordinator-tests with amore involved new_test

* Use a recursive async function to spawn `n` DockerTests with the necessary networking configuration

* Merge UNIQUE_ID and ONE_AT_A_TIME

* Tidy up the new recursive code in tests/coordinator

* Use a Mutex in CONTEXT to let it be set multiple times

* Make complimentary edits to full-stack tests

* Augment coordinator P2p connection logs

* Drop lock acquisitions before recursing

* Better scope lock acquisitions in full-stack, preventing a deadlock

* Ensure OUTER_OPS is reset across the test boundary

* Add cargo deny allowance for dockertest fork

coordinator/src/main.rs

@@ -951,10 +951,8 @@ pub async fn run<D: Db, Pro: Processors, P: P2p>(
   key: Zeroizing<<Ristretto as Ciphersuite>::F>,
   p2p: P,
   processors: Pro,
-  serai: Serai,
+  serai: Arc<Serai>,
 ) {
-  let serai = Arc::new(serai);
-
   let (new_tributary_spec_send, mut new_tributary_spec_recv) = mpsc::unbounded_channel();
   // Reload active tributaries from the database
   for spec in ActiveTributaryDb::active_tributaries(&raw_db).1 {
@@ -1212,11 +1210,10 @@ async fn main() {
     key_bytes.zeroize();
     key
   };
-  let p2p = LibP2p::new();
 
   let processors = Arc::new(MessageQueue::from_env(Service::Coordinator));
 
-  let serai = || async {
+  let serai = (async {
     loop {
       let Ok(serai) = Serai::new(format!(
         "http://{}:9944",
@@ -1229,8 +1226,10 @@ async fn main() {
         continue;
       };
       log::info!("made initial connection to Serai node");
-      return serai;
+      return Arc::new(serai);
     }
-  };
-  run(db, key, p2p, processors, serai().await).await
+  })
+  .await;
+  let p2p = LibP2p::new(serai.clone());
+  run(db, key, p2p, processors, serai).await
 }