ETA: Tutorials for tensor-based offline reconstruction, SLAC, and SfS

### 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

According to the current [documentation](http://www.open3d.org/docs/latest/tutorial/t_reconstruction_system/index.html):

> The tutorials for tensor-based offline reconstruction system, Simultaneous localization and calibration (SLAC), and shape from shading (SfS) tutorials as mentioned in [[Dong2021]](http://www.open3d.org/docs/release/tutorial/reference.html#dong2021) are still under construction.

I did not find a corresponding issue. What is the current status and ETA?