Backend cpp for model-based semantic segmentation

[DamienGilliard]

In this branch we develop the backend of df cpp library to allow the model-based semantic segmentation.

[DamienGilliard]

update:

• The point association now uses face triangles instead of sampling points on the mesh pace and doing a p2p association. Works much better (the black points are the associated ones)
• open3d is used for normal estimation instead of cilantro
• current total computation time on point cloud of half a million points: 1400 ms

to do:

• fix the reason why on some faces, a lot of points are excluded when they should be included
• de-couple functions such as normal estimation, to make components more flexible (already discussed, not done yet)

[DamienGilliard]

@9and3 I believe we can start the Ping-Pong (it took a bit longer than planned because a bird 🐦 flew through the window in the office, and getting it out became my mission. Birds don't know what's good for them...)

from top to bottom, the result of what this branch does: the rest of the clusters after the function is called, all the segments, with the selected points in black, and the selected point only.

[9and3]

btw, the results are starting to look fine! 🥇

[DamienGilliard]

Ok @9and3 , I'll check that tomorrow ! In the mean time, I have a refinement function, with promising results, for now. I'll do a quick wrap and see how it fares in Rhino, so we can discuss it tomorrow. The green part in the image is what is correctly added by the refinement function

[DamienGilliard]

@9and3 I believe this PR is ready to be reviewed and merged if it's ok ! I have also added quite a few defensive checks