*: remove NextConsensus mentions from dBFT API

NextConsensus API is not used by the users of dBFT. NextConsensus
handling (proposal, verification and agrreement) is moved to the upper
level of dBFT users. Starting from this commit NextConsensus
verification should be performed by dBFT user manually in
WithVerifyPrepareRequest callback.

A part of #84.

Signed-off-by: Anna Shaleva <[email protected]>

block.go

@@ -1,7 +1,7 @@
 package dbft
 
 // Block is a generic interface for a block used by dbft.
-type Block[H Hash, A Address] interface {
+type Block[H Hash] interface {
 	// Hash returns block hash.
 	Hash() H
 
@@ -16,8 +16,6 @@ type Block[H Hash, A Address] interface {
 	Index() uint32
 	// ConsensusData is a random nonce.
 	ConsensusData() uint64
-	// NextConsensus returns hash of the validators of the next block.
-	NextConsensus() A
 
 	// Signature returns block's signature.
 	Signature() []byte

check.go

@@ -4,7 +4,7 @@ import (
 	"go.uber.org/zap"
 )
 
-func (d *DBFT[H, A]) checkPrepare() {
+func (d *DBFT[H]) checkPrepare() {
 	if !d.hasAllTransactions() {
 		d.Logger.Debug("check prepare: some transactions are missing", zap.Any("hashes", d.MissingTransactions))
 		return
@@ -36,7 +36,7 @@ func (d *DBFT[H, A]) checkPrepare() {
 	}
 }
 
-func (d *DBFT[H, A]) checkCommit() {
+func (d *DBFT[H]) checkCommit() {
 	if !d.hasAllTransactions() {
 		d.Logger.Debug("check commit: some transactions are missing", zap.Any("hashes", d.MissingTransactions))
 		return
@@ -77,7 +77,7 @@ func (d *DBFT[H, A]) checkCommit() {
 	// new height.
 }
 
-func (d *DBFT[H, A]) checkChangeView(view byte) {
+func (d *DBFT[H]) checkChangeView(view byte) {
 	if d.ViewNumber >= view {
 		return
 	}