[#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>

cmd/neofs-node/netmap.go

@@ -167,10 +167,24 @@ func (c *cfg) localNodeInfoFromNetmap(nm *netmapSDK.Netmap) *netmapSDK.NodeInfo
 	return nil
 }
 
+// addNewEpochNotificationHandler adds handler that will be executed synchronously
 func addNewEpochNotificationHandler(c *cfg, h event.Handler) {
 	addNetmapNotificationHandler(c, newEpochNotification, h)
 }
 
+// addNewEpochAsyncNotificationHandler adds handler that will be executed asynchronously via netmap workerPool
+func addNewEpochAsyncNotificationHandler(c *cfg, h event.Handler) {
+	addNetmapNotificationHandler(
+		c,
+		newEpochNotification,
+		event.WorkerPoolHandler(
+			c.cfgNetmap.workerPool,
+			h,
+			c.log,
+		),
+	)
+}
+
 func goOffline(c *cfg) {
 	err := c.cfgNetmap.wrapper.UpdatePeerState(
 		crypto.MarshalPublicKey(&c.key.PublicKey),