This commit removes all EEVEE specific code from the `gpu_shader_material*.glsl` files. It defines a clear interface to evaluate the closure nodes leaving more flexibility to the render engine. Some of the long standing workaround are fixed: - bump mapping support is no longer duplicating a lot of node and is instead compiled into a function call. - bump rewiring to Normal socket is no longer needed as we now use a global `g_data.N` for that. Closure sampling with upstread weight eval is now supported if the engine needs it. This also makes all the material GLSL sources use `GPUSource` for better debugging experience. The `GPUFunction` parsing now happens in `GPUSource` creation. The whole `GPUCodegen` now uses the `ShaderCreateInfo` and is object type agnostic. Is has also been rewritten in C++. This patch changes a view behavior for EEVEE: - Mix shader node factor imput is now clamped. - Tangent Vector displacement behavior is now matching cycles. - The chosen BSDF used for SSR might change. - Hair shading may have very small changes on very large hairs when using hair polygon stripes. - ShaderToRGB node will remove any SSR and SSS form a shader. - SSS radius input now is no longer a scaling factor but defines an average radius. The SSS kernel "shape" (radii) are still defined by the socket default values. Appart from the listed changes no other regressions are expected.