demos: Add setup for plain js demos (#2288)

* add basic js demo

* improve js demos

* change demo button

* fix js demos on build

* add tailwind experiment

* docs: replace tailwind demo

Co-authored-by: Philipp Kühn <philippkuehn@MacBook-Pro-von-Philipp.local>

demos/setup/js.ts

@@ -0,0 +1,11 @@
+import 'iframe-resizer/js/iframeResizer.contentWindow'
+import { debug } from './helper'
+import './style.scss'
+
+export default function init(name: string, source: any) {
+  // @ts-ignore
+  window.source = source
+  document.title = name
+
+  debug()
+}