Add point cloud processing and random point cloud publishing nodes

- Implemented PointCloudProcessor for handling point cloud data and stopping trajectory based on point density.
- Added RandomPointCloudPublisher for generating and publishing random point clouds.
- Updated setup.py to include the new random point cloud node.
- Created visual representation of robot components using trimesh.
- Refactored test_transform.py to improve transform handling and removed unused imports.
- Added rosgraph.png to documentation.