Move shaders into glsl and hlsl directories

Move `data/shaders` to `data/shaders/glsl`
Move `data/hlsl` to `data/shaders/hlsl`

Fix up shader paths in the cpp files to point to the new glsl location.

`data/shaders/hlsl/compile.py` still overwrites the glsl .spv files (for
now).

Issue: #723

data/shaders/hlsl/deferredmultisampling/mrt.frag

@@ -0,0 +1,40 @@
+// Copyright 2020 Google LLC
+
+Texture2D textureColor : register(t1);
+SamplerState samplerColor : register(s1);
+Texture2D textureNormalMap : register(t2);
+SamplerState samplerNormalMap : register(s2);
+
+struct VSOutput
+{
+[[vk::location(0)]] float3 Normal : NORMAL0;
+[[vk::location(1)]] float2 UV : TEXCOORD0;
+[[vk::location(2)]] float3 Color : COLOR0;
+[[vk::location(3)]] float3 WorldPos : POSITION0;
+[[vk::location(4)]] float3 Tangent : TEXCOORD1;
+};
+
+struct FSOutput
+{
+	float4 Position : SV_TARGET0;
+	float4 Normal : SV_TARGET1;
+	float4 Albedo : SV_TARGET2;
+};
+
+FSOutput main(VSOutput input)
+{
+	FSOutput output = (FSOutput)0;
+	output.Position = float4(input.WorldPos, 1.0);
+
+	// Calculate normal in tangent space
+	float3 N = normalize(input.Normal);
+	N.y = -N.y;
+	float3 T = normalize(input.Tangent);
+	float3 B = cross(N, T);
+	float3x3 TBN = float3x3(T, B, N);
+	float3 tnorm = mul(normalize(textureNormalMap.Sample(samplerNormalMap, input.UV).xyz * 2.0 - float3(1.0, 1.0, 1.0)), TBN);
+	output.Normal = float4(tnorm, 1.0);
+
+	output.Albedo = textureColor.Sample(samplerColor, input.UV);
+	return output;
+}