add w_battery emissive material

valve/pbr/models/w_battery.mdl/w_battery.mdl.mat

@@ -21,6 +21,9 @@
 //"normal_map" "batside_normal.png"
 //"metal_map" "batside_metal.png"
 //"roughness_map" "batside_roughness.png"
+"emissive_map" "batside_emissive.png"
+//"emissive_map" "batside_emissive2.png"
+"emissive" "5 5 5"
 }
 
 {