Enhancement/boundary_mesh_transform

[timfelle]

• Allow the boundary meshes for the brinkman terms to be transformed. This should help place objects from external sources in a coherent way and scaled logically.
• Additionally, the number of elements in a tri_mesh_t is now correctly assigned and available.
• The immersed_bunny example is now set in a 4x1x1 domain and uses the new scaling to place the bunny in the domain.
• A few quality of life changes was made to the aabb type as well.