Minimal public chat under `/chat`

[pieroit]

Create a /chat endpoint serving:

• a minimal index.html (basic layout)
• a main.css
• widget-vue.js for the chat widget (see Create widget-vue.js to chat with the Cat from any webpage #269 )

This page will be ready to be customized by devs and is intended to be the starting point to build the public facing interface for the cat.

[pieroit]

Public chat done, yet to improve but present!
Go under http://localhost:1865/public