Make shader list and program file names more consistent

In particular, the client was loading list.txt, not shader_list.txt
and it seems weird to be incoherent between the source and built
resources in this way.

src/client/client_imgui.cpp

@@ -107,7 +107,7 @@ int main(int argc, char** argv)
     // @BUG This is a temporary hack. When shader_program_registry is grown, the existing
     // entries lose data.
     shader_program_registry.reserve(10);
-    loadShaderProgramsFromFile("shaders/shader_programs.txt", &shader_registry, &shader_program_registry);
+    loadShaderProgramsFromFile("shaders/programs.txt", &shader_registry, &shader_program_registry);
     messager.registerCallback(&debug_messagebus_callback);
     int window_height, window_width;
     glm::mat4 projection;