Added config-variants example

- IsolatedWorkspace will be reused in future updates as GLOBALS.MAKE_CONFIG access strategy.

examples/config-variants/build-config/script/header.js

@@ -0,0 +1,15 @@
+let ticking = 0;
+
+Callback.addCallback("LocalTick", function() {
+	ticking++;
+	if (ticking % 20 == 0) {
+		if (ticking == 1200) {
+			ticking = 0;
+		}
+		Game.tipMessage(ticking / 20);
+	}
+});
+
+Callback.addCallback("LocalLevelLoaded", function() {
+	ticking = 0;
+});