Needed to fix T61196, supporting clipped back-buffer in the 3D view which is done outside the draw module. It was also inconvenient having DRW_shader_* versions of GPU_shader_* API calls. - Clipping distances are now supported as a shader configuration for builtin shaders. - Add shader config argument when accessing builtin shaders. - Move GPU_shader_create_from_arrays() from DRW to GPU.