add DeliverTx hook (#521)

## Describe your changes and provide context

## Testing performed to validate your change

baseapp/abci.go

@@ -327,6 +327,9 @@ func (app *BaseApp) DeliverTx(ctx sdk.Context, req abci.RequestDeliverTx, tx sdk
 			resultStr = "failed"
 		}
 	}
+	for _, hook := range app.deliverTxHooks {
+		hook(ctx, tx, checksum, res)
+	}
 	return
 }
 

baseapp/baseapp.go

@@ -75,6 +75,8 @@ type (
 	// an older version of the software. In particular, if a module changed the substore key name
 	// (or removed a substore) between two versions of the software.
 	StoreLoader func(ms sdk.CommitMultiStore) error
+
+	DeliverTxHook func(sdk.Context, sdk.Tx, [32]byte, abci.ResponseDeliverTx)
 )
 
 // BaseApp reflects the ABCI application implementation.
@@ -172,6 +174,8 @@ type BaseApp struct { //nolint: maligned
 
 	concurrencyWorkers int
 	occEnabled         bool
+
+	deliverTxHooks []DeliverTxHook
 }
 
 type appStore struct {
@@ -279,6 +283,7 @@ func NewBaseApp(
 		},
 		commitLock:       &sync.Mutex{},
 		checkTxStateLock: &sync.RWMutex{},
+		deliverTxHooks:   []DeliverTxHook{},
 	}
 
 	app.TracingInfo.SetContext(context.Background())
@@ -1203,3 +1208,7 @@ func (app *BaseApp) GetCheckCtx() sdk.Context {
 	defer app.checkTxStateLock.RUnlock()
 	return app.checkState.ctx
 }
+
+func (app *BaseApp) RegisterDeliverTxHook(hook DeliverTxHook) {
+	app.deliverTxHooks = append(app.deliverTxHooks, hook)
+}