[examples] Make -functions example the default (#3541)

* Remove now-examples references

* Adjust gatsby example

* Adjust svelte example

* Adjust vanilla example

examples/svelte/api/date.js

@@ -0,0 +1,4 @@
+module.exports = (req, res) => {
+  const date = new Date().toString();
+  res.status(200).send(date);
+};