Implement Vulkan renderer

[LunaTheFoxgirl]

The plan is to have a vulkan renderer once the opengl renderer is in a good position. With the pppack tool being able to pack vulkan and opengl shaders together so the engine can dynamically load the shader for the graphics backend being used.

More stuff needs to be ironed out, ideas, or PRs would be appriciated.

• Implement Renderer class with static members invoking backend rendering
• Implement Vulkan structs as classes (possibly with nogc)
• Get ClearColor working with vulkan
• Get ClearDepth working with vulkan
• Get SpriteBatch working with vulkan
• Follow development of GL backend with vulkan