feat: basic shadow map + renderdoc labels

destrum/assets_src/shaders/shadow.vert

@@ -0,0 +1,12 @@
+#version 460
+
+#extension GL_GOOGLE_include_directive : require
+
+#include "mesh_pcs.glsl"
+
+void main()
+{
+    Vertex v = pcs.vertexBuffer.vertices[gl_VertexIndex];
+
+    gl_Position = pcs.sceneData.lightViewProj * pcs.transform * vec4(v.position, 1.0f);
+}