ldr_wgpu high performance realtime LDraw renderer

[Max Murtazin]

I've made some more improvements to rendering performance and loading times. I've also implemented calculation of normals using an angle threshold as well as splitting edges similar to what I do for the Blender addon ldr_tools_blender. The edge splitting is in its own module in the source code with associated unit tests for reference. The implementation is inspired by Blender but is implemented slightly differently.

Using angle threshold method is not the best thing to do. LDraw models are relatively low-polygonal, and angle threshold would more likely lead to unnecessary edge splitting

Suggest using either edge splitting by absence of condline or presence of line. I believe prior is done by LDView