Adding a curated list of annotation tools for 3D CAD Models

[dhirajsuvarna]

Hi,

It would really help if a curated list of tools for 3d CAD Models is also added in this list.

For Eg.

1. Tools for Segmenting the CAD Model
2. Tools for Converting the CAD Models from one format to another.

PS: I am still in the processing of finding tool for Segmenting a CAD Model to create a custom training dataset. Since this github repo was my first go to point, I was disappointed when i didn't fine any tools here. Hence this issue.