Make core:image packages work on js platform (wasm32) by not requiring core:os

core/image/netpbm/netpbm_js.odin

@@ -0,0 +1,10 @@
+//+build js
+package netpbm
+
+load :: proc {
+	load_from_bytes,
+}
+
+save :: proc {
+	save_to_buffer,
+}