add reasons to slash evidence (#414)

* add reasons to slash evidence

* fix CI failing

* Remove unnecessary clones

.encode() takes &self

* InvalidVr to InvalidValidRound

* Unrelated to this PR: Clarify reasoning/potentials behind dropping evidence

* Clarify prevotes in SlashEvidence test

* Replace use of read_to_end

* Restore decode_signed_message

---------

Co-authored-by: Luke Parker <lukeparker5132@gmail.com>

coordinator/tributary/tendermint/src/ext.rs

@@ -282,7 +282,7 @@ pub trait Network: Sized + Send + Sync {
   /// Trigger a slash for the validator in question who was definitively malicious.
   ///
   /// The exact process of triggering a slash is undefined and left to the network as a whole.
-  async fn slash(&mut self, validator: Self::ValidatorId, slash_event: SlashEvent<Self>);
+  async fn slash(&mut self, validator: Self::ValidatorId, slash_event: SlashEvent);
 
   /// Validate a block.
   async fn validate(&mut self, block: &Self::Block) -> Result<(), BlockError>;