jekyll: move jekyll back to root, but simpler setup, exclude via _config.yml

app: bundle jekyll docs into app, add 'yarn run docs' to build
ui: add back/forward arrows for app only, adjust responsiveness for app, add IS_APP flag injected via preload
ui: add animated logo, friendly message on empty replay frame
app: improve serve logic:
- serve static files from static root
- serve replay from http localhost instead to avoid proxying https for remote requests
- serve local lookup from http prefix also
- catch any fallthrough from replay as 404
- add timestamp to response channels to ensure uniqness

index.html

@@ -0,0 +1,10 @@
+<!doctype html>
+<html class="no-overflow">
+<head>
+<script src="./frontend.js"></script>
+<!--<link href="./dist/frontend.css" rel="stylesheet"/>-->
+</head>
+<body>
+<app-main></app-main>
+</body>
+</html>