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/depthpass.vert

@@ -0,0 +1,29 @@
+#version 450
+
+layout (location = 0) in vec3 inPos;
+layout (location = 1) in vec2 inUV;
+
+// todo: pass via specialization constant
+#define SHADOW_MAP_CASCADE_COUNT 4
+
+layout(push_constant) uniform PushConsts {
+	vec4 position;
+	uint cascadeIndex;
+} pushConsts;
+
+layout (binding = 0) uniform UBO {
+	mat4[SHADOW_MAP_CASCADE_COUNT] cascadeViewProjMat;
+} ubo;
+
+layout (location = 0) out vec2 outUV;
+
+out gl_PerVertex {
+	vec4 gl_Position;   
+};
+
+void main()
+{
+	outUV = inUV;
+	vec3 pos = inPos + pushConsts.position.xyz;
+	gl_Position =  ubo.cascadeViewProjMat[pushConsts.cascadeIndex] * vec4(pos, 1.0);
+}