reorg dir structure:

- keep shared and electron build at root
- move static files for replayweb.page and Jekyll config to docs/
- move Jekyll markdown to docs/docs/

docs/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>