This is a massive cleanup needed for vulkan support T68990. It provides: - More meaningful enums with conversion functions. - Less hacky supports of arrays and cubemaps (all considered layered). - More inline with the stateless design of vulkan and modern GL. - Methods Fallbacks are using framebuffer functions that are wrapped instead of implementing inside the texture module. What is not in there: - API change. - Samplers support (breaks a few effects). # Conflicts: # source/blender/gpu/GPU_texture.h