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

_config.yml

@@ -0,0 +1,42 @@
+remote_theme: pmarsceill/just-the-docs
+#theme: "just-the-docs"
+
+title: ReplayWeb.Page
+
+# Enable or disable the site search
+search_enabled: false
+
+# Set the search token separator for hyphenated-word search:
+search_tokenizer_separator: /[\s/]+/
+
+# Enable or disable heading anchors
+heading_anchors: true
+
+# Aux links for the upper right navigation
+aux_links:
+  "Back to ReplayWeb.page":
+    - "/"
+
+logo: "/assets/logo.svg"
+
+plugins:
+  - jekyll-remote-theme
+
+
+baseUrl: '/'
+
+exclude:
+  - Gemfile
+  - Gemfile.lock
+  - package.json
+  - run.sh
+  - webpack.config.js
+  - yarn-error.log
+  - yarn.lock
+  - local-examples/
+  - build/
+  - src/
+  - dist/
+  - node_modules/
+  - plugins/
+