[#11] Use gRPC handlers in neofs-node application

Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>

cmd/neofs-node/config.go

@@ -1,11 +1,22 @@
 package main
 
+import (
+	"context"
+	"sync"
+)
+
 type cfg struct {
+	ctx context.Context
+
+	wg *sync.WaitGroup
+
 	grpcAddr string
 }
 
 func defaultCfg() *cfg {
 	return &cfg{
-		grpcAddr: ":50501",
+		ctx:      context.Background(),
+		wg:       new(sync.WaitGroup),
+		grpcAddr: "127.0.0.1:50501",
 	}
 }