LAStools support

[mbredif]

LAStools has evolved since CGAL forked it in https://github.com/CGAL/LAStools. I think we can now try to use it directly.

• LAStools now supports Cmake natively
• Among other new features, LAStools now support the COPC extension, which enables embedding an octree section in the las/laz (a VLR) for efficient pruning of the point range given a query 3D bbox.
• Version 240319 introduces a breaking change in the constructor of all LASreaders. They now expect a LASreadOpener* argument : https://github.com/LAStools/LAStools/commit/c3012b6e94ba7abc90236faa4899bf34d38b4dc8 See also this reported issue
• Missing functions in the dll. See this pull request

[afabri]

@soesau can you check if we can switch to the latest version.