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/indirectdraw/skysphere.vert

@@ -1,25 +0,0 @@
-#version 450
-
-// Vertex attributes
-layout (location = 0) in vec4 inPos;
-layout (location = 2) in vec2 inUV;
-
-layout (binding = 0) uniform UBO 
-{
-	mat4 projection;
-	mat4 modelview;
-} ubo;
-
-layout (location = 0) out vec2 outUV;
-
-out gl_PerVertex
-{
-	vec4 gl_Position;
-};
-
-void main() 
-{
-	outUV = vec2(inUV.s, 1.0-inUV.t);
-	// Skysphere always at center, only use rotation part of modelview matrix
-	gl_Position = ubo.projection * mat4(mat3(ubo.modelview)) * vec4(inPos.xyz, 1.0);
-}