[#476] reputation: Make reputation report async

Add handler closure over worker pool
in the event package.
Add `addNewEpochAsyncNotificationHandler`
function that uses that closure. Pass
the reputation report handler to worker
pool via using that function.

Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>

pkg/morph/event/utils.go

@@ -1,6 +1,10 @@
 package event
 
-import "github.com/nspcc-dev/neo-go/pkg/util"
+import (
+	"github.com/nspcc-dev/neo-go/pkg/util"
+	util2 "github.com/nspcc-dev/neofs-node/pkg/util"
+	"go.uber.org/zap"
+)
 
 type scriptHashValue struct {
 	hash util.Uint160
@@ -34,3 +38,18 @@ func (s *typeValue) SetType(v Type) {
 func (s typeValue) GetType() Type {
 	return s.typ
 }
+
+// WorkerPoolHandler sets closure over worker pool w with passed handler h.
+func WorkerPoolHandler(w util2.WorkerPool, h Handler, log *zap.Logger) Handler {
+	return func(e Event) {
+		err := w.Submit(func() {
+			h(e)
+		})
+
+		if err != nil {
+			log.Warn("could not Submit handler to worker pool",
+				zap.String("error", err.Error()),
+			)
+		}
+	}
+}