message: insert sorted vertices in batch to avoid quadratic behaviour in the simplex tree
diff: #include <string>
  #include <cstddef> // for std::size_t
  #include <optional>
  +#include <numeric> // for std::iota
  #ifdef GUDHI_USE_TBB
  #include <tbb/parallel_for.h>
  @@ -624,6 +625,12 @@ class Tangential_complex {
  int max_dim = -1;
  + // Vertices to be inserted first by the create_complex method to avoid quadratic complexity.
  + // It isn't just [0, n) if some points have multiplicity (only one copy appears in the complex).
  + std::vector<typename Simplex_tree_::Vertex_handle> vertices(m_points.size());
  + std::iota(vertices.begin(), vertices.end(), 0);
  + tree.insert_batch_vertices(vertices);
  +
  // For each triangulation
  for (std::size_t idx = 0; idx < m_points.size(); ++idx) {
  // For each cell of the star
  