This function was a duplicate of the `(*StorageEngine).addShard`
but it didn't allow to set an engine's shard pool size what can
be very useful sometimes.

Signed-off-by: Aleksey Savchuk <a.savchuk@yadro.com>

@@ -99,0 +91,4 @@
+	for _, addr := range prm.addrs {
+		select {
+		case <-ctx.Done():
+			taskCancel(context.Cause(ctx))

@@ -99,0 +96,4 @@
+		}
+
+		wg.Add(1)
+		if err := e.inhumePool.Submit(func() {

@@ -131,0 +135,4 @@
+//
+// If checkLocked is set, [apistatus.ObjectLocked] will be returned if any of
+// the objects are locked.
+func (e *StorageEngine) groupObjectsByShard(ctx context.Context, addrs []oid.Address, checkLocked bool) (map[string][]int, error) {

@@ -100,0 +93,4 @@
+
+	var errLocked *apistatus.ObjectLocked
+
+	for shardID, addrIndexes := range addrsPerShard {