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

tests/embed/index-sandbox.html

@@ -1,19 +1,24 @@
 <!doctype html>
 <html>
-<head>
-<script src="http://localhost:9990/ui.js"></script>
-<style>
-html, body {
-  background-color: lightgrey;
-  height: 100%;
-  width: 100%;
-  overflow: hidden;
-}
-</style>
-</head>
-<body>
-
-<replay-web-page embed="replay" src="http://localhost:9990/docs/assets/tweet-example.wacz" url="page:0" sandbox requiresubdomainiframe></replay-web-page>
-
-</body>
+  <head>
+    <script src="http://localhost:9990/ui.js"></script>
+    <style>
+      html,
+      body {
+        background-color: lightgrey;
+        height: 100%;
+        width: 100%;
+        overflow: hidden;
+      }
+    </style>
+  </head>
+  <body>
+    <replay-web-page
+      embed="replay"
+      src="http://localhost:9990/docs/examples/tweet-example.wacz"
+      url="page:0"
+      sandbox
+      requiresubdomainiframe
+    ></replay-web-page>
+  </body>
 </html>