Replace bincode with borsh (#452)

* Add SignalsConfig to chain_spec

* Correct multiexp feature flagging for rand_core std

* Remove bincode for borsh

Replaces a non-canonical encoding with a canonical encoding which additionally
should be faster.

Also fixes an issue where we used bincode in transcripts where it cannot be
trusted.

This ended up fixing a myriad of other bugs observed, unfortunately.
Accordingly, it either has to be merged or the bug fixes from it must be ported
to a new PR.

* Make serde optional, minimize usage

* Make borsh an optional dependency of substrate/ crates

* Remove unused dependencies

* Use [u8; 64] where possible in the processor messages

* Correct borsh feature flagging

coordinator/src/main.rs

@@ -21,7 +21,7 @@ use serai_env as env;
 use scale::Encode;
 use serai_client::{
   primitives::NetworkId,
-  validator_sets::primitives::{Session, ValidatorSet},
+  validator_sets::primitives::{Session, ValidatorSet, KeyPair},
   Public, Serai, SeraiInInstructions,
 };
 
@@ -501,7 +501,7 @@ async fn handle_processor_message<D: Db, P: P2p>(
             &mut txn,
             key,
             spec,
-            &(Public(substrate_key), network_key.try_into().unwrap()),
+            &KeyPair(Public(substrate_key), network_key.try_into().unwrap()),
             id.attempt,
           );
 
@@ -587,7 +587,7 @@ async fn handle_processor_message<D: Db, P: P2p>(
           vec![Transaction::SubstratePreprocess(SignData {
             plan: id.id,
             attempt: id.attempt,
-            data: preprocesses,
+            data: preprocesses.into_iter().map(Into::into).collect(),
             signed: Transaction::empty_signed(),
           })]
         }
@@ -612,7 +612,7 @@ async fn handle_processor_message<D: Db, P: P2p>(
                 };
                 id.encode()
               },
-              preprocesses,
+              preprocesses.into_iter().map(Into::into).collect(),
             );
 
             let intended = Transaction::Batch(
@@ -681,7 +681,7 @@ async fn handle_processor_message<D: Db, P: P2p>(
             vec![Transaction::SubstratePreprocess(SignData {
               plan: id.id,
               attempt: id.attempt,
-              data: preprocesses,
+              data: preprocesses.into_iter().map(Into::into).collect(),
               signed: Transaction::empty_signed(),
             })]
           }