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/geometryshader/normaldebug.geom

@@ -0,0 +1,43 @@
+// Copyright 2020 Google LLC
+
+struct UBO
+{
+	float4x4 projection;
+	float4x4 model;
+};
+
+cbuffer ubo : register(b1) { UBO ubo; }
+
+struct VSOutput
+{
+[[vk::location(0)]] float4 Pos : POSITION0;
+[[vk::location(1)]] float3 Normal : NORMAL0;
+};
+
+struct GSOutput
+{
+	float4 Pos : SV_POSITION;
+[[vk::location(0)]] float3 Color : COLOR0;
+};
+
+[maxvertexcount(6)]
+void main(triangle VSOutput input[3], inout LineStream<GSOutput> outStream)
+{
+	float normalLength = 0.02;
+	for(int i=0; i<3; i++)
+	{
+		float3 pos = input[i].Pos.xyz;
+		float3 normal = input[i].Normal.xyz;
+
+		GSOutput output = (GSOutput)0;
+		output.Pos = mul(ubo.projection, mul(ubo.model, float4(pos, 1.0)));
+		output.Color = float3(1.0, 0.0, 0.0);
+		outStream.Append( output );
+
+		output.Pos = mul(ubo.projection, mul(ubo.model, float4(pos + normal * normalLength, 1.0)));
+		output.Color = float3(0.0, 0.0, 1.0);
+		outStream.Append( output );
+
+		outStream.RestartStrip();
+	}
+}