Add RebuildBatched (#23)

Original `Rebuild` was making thousands of individual update queries. I
added `RebuildBatched` which can becalled as:

```go
nestedset.RebuildBatched(db.WithContext(ctx), root, true, 1000)
```

Fixed the rebuild order confused

Changed rebuild update args

To enable the rebuild dirty run

Merge pull request #20 from longbridgeapp/rebuild

Added the rebuild function

To sync the children_count after Deleted

To upgrade the github workflows go version

Merge pull request #18 from wenlingang/main

fix not enough arguments in call to schemaField.ValueOf

Update go mod path

Fix indent