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/texturemipmapgen/texture.frag

@@ -1,26 +0,0 @@
-#version 450
-
-layout (set = 0, binding = 1) uniform texture2D textureColor;
-layout (set = 0, binding = 2) uniform sampler samplers[3];
-
-layout (location = 0) in vec2 inUV;
-layout (location = 1) in float inLodBias;
-layout (location = 2) flat in int inSamplerIndex;
-layout (location = 3) in vec3 inNormal;
-layout (location = 4) in vec3 inViewVec;
-layout (location = 5) in vec3 inLightVec;
-
-layout (location = 0) out vec4 outFragColor;
-
-void main() 
-{
-	vec4 color = texture(sampler2D(textureColor, samplers[inSamplerIndex]), inUV, inLodBias);
-
-	vec3 N = normalize(inNormal);
-	vec3 L = normalize(inLightVec);
-	vec3 V = normalize(inViewVec);
-	vec3 R = reflect(L, N);
-	vec3 diffuse = max(dot(N, L), 0.65) * vec3(1.0);
-	float specular = pow(max(dot(R, V), 0.0), 16.0) * color.a;
-	outFragColor = vec4(diffuse * color.rgb + specular, 1.0);	
-}