* Significant refactor of the Routes plugin

- More modular and OOP
- Better Roda plugin layout
- Dynamic `index` route now supported instead of static index.html
- Downstream plugins can leverage file-based routing themselves

* Move monkey-patched Roda Public code into streamlined standalone SSG plugin

- Also serve static `index.html` using the same `Rack::Files` server

* # SSR mode and Fast Refresh mode are mutually exclusive

* add comment

* Simplify by moving more Roda-specific code into the server plugin