Generate NormalMaps and HeightMaps

[Thomas-Zorroche]

Generate normal maps and height maps from a high poly model in order to retrieve details on a decimated mesh.
This PR is linked to the following in the meshroom repository : alicevision/Meshroom#1508

Documentation

Plug the high poly mesh output from the Meshing into the Texturing Ref mesh input.
Then plug the low poly model to export into the Texturing mesh input.

Implementation remarks

• It is possible to skip a texture generation (Diffuse, NormalMap, HeightMap) by choosing the empty option for the texture file type.
• Heightmaps can only be exported in .exr format.
• In order to have correct results, you should not use a "simple" Decimate node with a vertices count target. Instead, use as many combinations of MeshFiltering following by Decimate node as needed, then use the output mesh as the model to texture.

Screenshot

Rendered in Cycles (Diffuse + NormalMaps)
Model with 6 411 triangles.

[fabiencastan]

@Thomas-Zorroche Could you upgrade the main_convertMesh to use the library instead of geogram?