feat(runtime): Add example for extension with ops (#19204)

Spend quite some time trying to get this working. With proper example
would have been a lot faster. So this is pr with the example. I also
rearranged examples a little bit to allow for addition of more examples

runtime/examples/extension_with_esm/bootstrap.js

@@ -0,0 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+function hello() {
+  console.log("Hello from extension!");
+}
+globalThis.Extension = { hello };