Rotation oriented bounding box

### Checklist

- [X] I have searched for [similar issues](https://github.com/isl-org/Open3D/issues).
- [X] For Python issues, I have tested with the [latest development wheel](http://www.open3d.org/docs/latest/getting_started.html#development-version-pip).
- [X] I have checked the [release documentation](http://www.open3d.org/docs/release/) and the [latest documentation](http://www.open3d.org/docs/latest/) (for `master` branch).

### My Question

Hello!
Thank you for your great work! I would like to ask you a question about point cloud rotation.

I have two different point clouds:
Source
Target:
My goal is to obtain the same orientation of the target point cloud as the source's. I have already tried to use the rotation matrix from the oriented bounding box, but I still haven't been able so solve this issue using the rotation matrix.
Could you give me any advice?

Have a great day!