GPUDriver implementation

[SupinePandora43]

Implement a good GPUDriver using dotnet/Silk.Net for different APIs.

• Veldrid
• OpenGL
• Vulkan
• • Allocator
• • Pipelines
• • MSAA (with resolve renderpass targets)
• • Multiple frames per flight (use BitVector32 for counting frame ids)
• • Multithreading (block GPUDriver::BeginSynchronization until commands are processed)
• • ~~Handle OUT_OF_MEMORY (Renderer::PurgeMemory)
    ~~