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/particlefire/particle.vert

@@ -0,0 +1,45 @@
+#version 450
+
+layout (location = 0) in vec4 inPos;
+layout (location = 1) in vec4 inColor;
+layout (location = 2) in float inAlpha;
+layout (location = 3) in float inSize;
+layout (location = 4) in float inRotation;
+layout (location = 5) in int inType;
+
+layout (location = 0) out vec4 outColor;
+layout (location = 1) out float outAlpha;
+layout (location = 2) out flat int outType;
+layout (location = 3) out float outRotation;
+
+layout (binding = 0) uniform UBO 
+{
+	mat4 projection;
+	mat4 modelview;
+	vec2 viewportDim;
+	float pointSize;
+} ubo;
+
+out gl_PerVertex
+{
+	vec4 gl_Position;
+	float gl_PointSize;
+};
+
+void main () 
+{
+	outColor = inColor;
+	outAlpha = inAlpha;
+	outType = inType;
+	outRotation = inRotation;
+	  
+	gl_Position = ubo.projection * ubo.modelview * vec4(inPos.xyz, 1.0);	
+	
+	// Base size of the point sprites
+	float spriteSize = 8.0 * inSize;
+
+	// Scale particle size depending on camera projection
+	vec4 eyePos = ubo.modelview * vec4(inPos.xyz, 1.0);
+	vec4 projectedCorner = ubo.projection * vec4(0.5 * spriteSize, 0.5 * spriteSize, eyePos.z, eyePos.w);
+	gl_PointSize = ubo.viewportDim.x * projectedCorner.x / projectedCorner.w;	
+}