DA Live Preview (#256)

* DA Live Preview

Add live preview support for Document Authoring for customers who use the new Commerce Scaffold CLI.

## Note:
If there is no query param, the script will not be imported. Either way, this runs after loadPage and does not impact performance.

Before: https://main--aem-boilerplate-commerce--hlxsites.hlx.page/

After: https://da-live-preview--aem-boilerplate-commerce--hlxsites.hlx.page/

* Update 404.html

Remove use credentials.

1. This property is not necessary.
2. This property breaks da live preview.

---------

Co-authored-by: Stephen <[email protected]>

404.html

@@ -18,7 +18,7 @@
   </script>
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <meta property="og:title" content="Page not found">
-  <script src="/scripts/scripts.js" type="module" crossorigin="use-credentials"></script>
+  <script src="/scripts/scripts.js" type="module"></script>
   <script type="module">
     window.addEventListener('load', () => {
       if (document.referrer) {

scripts/scripts.js

@@ -374,3 +374,9 @@ async function loadPage() {
 }
 
 loadPage();
+
+(async function loadDa() {
+  if (!new URL(window.location.href).searchParams.get('dapreview')) return;
+  // eslint-disable-next-line import/no-unresolved
+  import('https://da.live/scripts/dapreview.js').then(({ default: daPreview }) => daPreview(loadPage));
+}());