[#1449] tree: Add ApplyBatch method

Concurrent Apply can lead to child node applies before parent, so
undo/redo operations will perform. This leads to performance degradation
in case of tree with many sublevels.

Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>

pkg/services/tree/options.go

@@ -41,6 +41,7 @@ type cfg struct {
 	replicatorTimeout         time.Duration
 	containerCacheSize        int
 	authorizedKeys            [][]byte
+	syncBatchSize             int
 
 	localOverrideStorage policyengine.LocalOverrideStorage
 	morphChainStorage    policyengine.MorphRuleChainStorageReader
@@ -113,6 +114,12 @@ func WithReplicationWorkerCount(n int) Option {
 	}
 }
 
+func WithSyncBatchSize(n int) Option {
+	return func(c *cfg) {
+		c.syncBatchSize = n
+	}
+}
+
 func WithContainerCacheSize(n int) Option {
 	return func(c *cfg) {
 		if n > 0 {