Documentation: Elaborate on url and webRoot properties

This is a request for clarifying documentation. I don't understand what problem `url` and/or `webRoot` solve:

> You may want (or need) to debug your application running on a Webserver (especially if it interacts with server-side components like Webservices).

I know when my app needs a running webserver, but I don't understand how these properties relate. I _hoped_ they fired up a web server and served my local frontend files through it. That use case comes up for me all the time, and it's time consuming to have to figure out which web server is the easiest to set up just so I can troubleshoot some HTML/JS's behavior when it's opened locally vs through a server.

I can't tell if that's what this feature does or not. To me, that quote could be interpreted either way. Can the readme include more details about what these properties do and when you need them?

Lee la sección del README que describe las propiedades url y webRoot y verifica en la documentación existente qué afecta cada propiedad y si inicia un servidor web. Actualiza el README para explicar su propósito, cuándo son necesarias y si se admite servir archivos locales del frontend.

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