Extract playground samples from mdoc, add possiblity to run them from source

website/playground/new-samples/customizing-the-appearence/exposed-css-classes/sample.js

@@ -0,0 +1,7 @@
+// The editor exposes a set of CSS classes that can be overwritten.
+monaco.editor.create(document.getElementById("container"), {
+	value: "My to-do list:\n* buy milk\n* buy coffee\n* write awesome code",
+	language: "text/plain",
+	fontFamily: "Arial",
+	fontSize: 20
+});