add kenney assets and start gui screen

example/kenney/lang.lua

@@ -0,0 +1,12 @@
+local M = {}
+
+local data = {
+	main_page = "Main page",
+}
+
+
+function M.get_locale(lang_id)
+	return data[lang_id] or lang_id
+end
+
+return M