remove combined {models,sprites}.mat, remove extra .mdl .spr exts

cstrike/pbr/models/v_knife_r.mdl/v_knife_r.mat

@@ -0,0 +1,18 @@
+
+{
+"for" "#models/v_knife_r/knife.mdl"
+//"basecolor_map" "knife.png"
+//"normal_map" "knife_normal.png"
+//"metal_map" "knife_metal.png"
+//"roughness_map" "knife_roughness.png"
+"metalness" "1"
+"roughness" "0"
+}
+
+{
+"for" "#models/v_knife_r/newhand.mdl"
+//"basecolor_map" "newhand.png"
+//"normal_map" "newhand_normal.png"
+//"metal_map" "newhand_metal.png"
+//"roughness_map" "newhand_roughness.png"
+}