feat: Add missing Polygon and Quad implementation for Bepu

https://github.com/stride3d/stride-community-toolkit/blob/main/src/Stride.CommunityToolkit/Rendering/ProceduralModels/Procedural2DModelBuilder.cs

1. Make sure existing `PolygonProceduralModel.cs` is correct
2. Make sure that `AddBepu2DPhysics()` it implements corretly, we might need to use something similar to existing `TriangularPrismCollider`