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/descriptorindexing/descriptorindexing.frag

@@ -0,0 +1,15 @@
+#version 450
+
+#extension GL_EXT_nonuniform_qualifier : require
+
+layout (set = 0, binding = 1) uniform sampler2D textures[];
+
+layout (location = 0) in vec2 inUV;
+layout (location = 1) flat in int inTexIndex;
+
+layout (location = 0) out vec4 outFragColor;
+
+void main() 
+{
+	outFragColor = texture(textures[nonuniformEXT(inTexIndex)], inUV);
+}

data/shaders/glsl/descriptorindexing/descriptorindexing.vert

@@ -0,0 +1,26 @@
+#version 450
+
+layout (location = 0) in vec3 inPos;
+layout (location = 1) in vec2 inUV;
+layout (location = 2) in int inTextureIndex;
+
+layout (binding = 0) uniform Matrices
+{
+	mat4 projection;
+	mat4 view;
+	mat4 model;
+} matrices;
+
+layout (location = 0) out vec2 outUV;
+layout (location = 1) flat out int outTexIndex;
+
+void main() 
+{
+	outUV = inUV;
+	outTexIndex = 0;
+	outTexIndex = inTextureIndex;
+	outTexIndex = gl_InstanceIndex;
+	vec4 pos = vec4(inPos, 1.0f);
+	pos.y += gl_InstanceIndex;
+	gl_Position = matrices.projection * matrices.view * matrices.model * pos;
+}