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/stencilbuffer/outline.vert

@@ -0,0 +1,24 @@
+#version 450
+
+layout (location = 0) in vec4 inPos;
+layout (location = 2) in vec3 inNormal;
+
+layout (binding = 0) uniform UBO 
+{
+	mat4 projection;
+	mat4 model;
+	vec4 lightPos;
+	float outlineWidth;
+} ubo;
+
+out gl_PerVertex
+{
+	vec4 gl_Position;
+};
+
+void main() 
+{
+	// Extrude along normal
+	vec4 pos = vec4(inPos.xyz + inNormal * ubo.outlineWidth, inPos.w);
+	gl_Position = ubo.projection * ubo.model * pos;
+}