[#59] Add grpc payload splitter in object service chain

GRPC has default message limit of 4MiB. Since every transmitted
neofs message has to be signed, then original message should
be split into transfer fit structures before signature service.

This commit introduce transport payload splitter for object
service pipeline. This splitter works with stream response
for methods:

  - object.Get
  - object.Range
  - object.Search

Signed-off-by: Alex Vanin <alexey@nspcc.ru>

cmd/neofs-node/object.go

@@ -253,15 +253,19 @@ func initObjectService(c *cfg) {
 		objectTransportGRPC.New(
 			objectService.NewSignService(
 				c.key,
-				&objectSvc{
-					put:     sPutV2,
-					search:  sSearchV2,
-					head:    sHeadV2,
-					rng:     sRangeV2,
-					get:     sGetV2,
-					rngHash: sRangeHashV2,
-					delete:  sDeleteV2,
-				},
+				objectService.NewTransportSplitter(
+					c.cfgGRPC.maxChunkSize,
+					c.cfgGRPC.maxAddrAmount,
+					&objectSvc{
+						put:     sPutV2,
+						search:  sSearchV2,
+						head:    sHeadV2,
+						rng:     sRangeV2,
+						get:     sGetV2,
+						rngHash: sRangeHashV2,
+						delete:  sDeleteV2,
+					},
+				),
 			),
 		),
 	)