add blank material files

gearbox/pbr/models/zombie_soldier.mdl/zombie_soldier.mdl.mat

@@ -0,0 +1,8 @@
+
+{
+"for" "#models/zombie_soldier/zombie_soldier.mdl"
+//"basecolor_map" "zombie_soldier.png"
+//"normal_map" "zombie_soldier_normal.png"
+//"metal_map" "zombie_soldier_metal.png"
+//"roughness_map" "zombie_soldier_roughness.png"
+}