How to transform each vertex of a mesh with a different transform matrix

### 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](https://www.open3d.org/docs/latest/getting_started.html#development-version-pip).
- [X] I have checked the [release documentation](https://www.open3d.org/docs/release/) and the [latest documentation](https://www.open3d.org/docs/latest/) (for `main` branch).

### My Question

I know that the whole mesh can be transformed by a single transformation matrix quickly. But how do I transform the vertices with different transformation matrices... if you haven't already figured out im basically doing skeletal animation, so each vertex gets transformed differently. I know I can just sequentially multiple the vertex with it's corresponding transformation... but this would be very slow. I need a faster method...