Site reorg: Remove site/ subpath (#306)

Unfortunately, for proper package pathing, need to remove the `site/`
subpath. This includes:
- Moving everything back into root
- Adding a `copy-site.sh` script to copy resources into `mkdocs/site/`
before building the site with mkdocs.
- Also update examples to ensure all are loading the local sw.js / ui.js
- Consolidate examples in `docs/examples`
- Consolidate assets under src/assets/
- Move `favicons` to root
- Reformat and relint
- Tests: update playwright tests to use mkdocs output, add test for
embed in docs
- bump to 2.0.0-beta.2

index.html

@@ -0,0 +1,15 @@
+<!doctype html>
+<html class="no-overflow">
+  <head>
+    <link rel="manifest" href="/webmanifest.json" />
+    <title>ReplayWeb.page</title>
+    <meta name="viewport" content="width=device-width, initial-scale=1" />
+    <script src="./ui.js"></script>
+    <link rel="icon" href="/favicons/favicon.ico" sizes="32x32" />
+    <link rel="icon" href="/favicons/favicon.svg" type="image/svg+xml" />
+    <link rel="apple-touch-icon" href="/favicons/apple-touch-icon.png" />
+  </head>
+  <body>
+    <replay-app-main></replay-app-main>
+  </body>
+</html>