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/shadowmappingcascade/debugshadowmap.vert

@@ -0,0 +1,20 @@
+#version 450
+
+layout(push_constant) uniform PushConsts {
+	vec4 position;
+	uint cascadeIndex;
+} pushConsts;
+
+layout (location = 0) out vec2 outUV;
+layout (location = 1) out uint outCascadeIndex;
+
+out gl_PerVertex {
+	vec4 gl_Position;   
+};
+
+void main() 
+{
+	outUV = vec2((gl_VertexIndex << 1) & 2, gl_VertexIndex & 2);
+	outCascadeIndex = pushConsts.cascadeIndex;
+	gl_Position = vec4(outUV * 2.0f - 1.0f, 0.0f, 1.0f);
+}