Move the code dealing with converting float3 to GPU normals out of the vertex format header into a separate header. Use a proper C++ namespace and remove duplication by only using the more recently added C++ templated conversions. Most of the diff comes from the removal of the indirect includes from GPU_vertex_format.hh. A lot of files ended up mistakenly depending on that. Pull Request: https://projects.blender.org/blender/blender/pulls/134873