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/glsl/ssao/gbuffer.frag

@@ -0,0 +1,26 @@
+#version 450
+
+layout (location = 0) in vec3 inNormal;
+layout (location = 1) in vec2 inUV;
+layout (location = 2) in vec3 inColor;
+layout (location = 3) in vec3 inPos;
+
+layout (location = 0) out vec4 outPosition;
+layout (location = 1) out vec4 outNormal;
+layout (location = 2) out vec4 outAlbedo;
+
+const float NEAR_PLANE = 0.1f; //todo: specialization const
+const float FAR_PLANE = 64.0f; //todo: specialization const 
+
+float linearDepth(float depth)
+{
+	float z = depth * 2.0f - 1.0f; 
+	return (2.0f * NEAR_PLANE * FAR_PLANE) / (FAR_PLANE + NEAR_PLANE - z * (FAR_PLANE - NEAR_PLANE));	
+}
+
+void main() 
+{
+	outPosition = vec4(inPos, linearDepth(gl_FragCoord.z));
+	outNormal = vec4(normalize(inNormal) * 0.5 + 0.5, 1.0);
+	outAlbedo = vec4(inColor * 2.0, 1.0);
+}