tweaks to sample program

Added support for React hot loading.

updated README to make it a bit clearer you need ViteJS tooling for t…

…his to work.

Added configuration for Vite running somewhere other than localhost:3…

…000.

Implement Alex Edwards directory listing blocker

removed some test code from the sample program

documented file server; added a test

tests for the integrated file server

document the weird embed.FS issue

fixed formatting of sample vite.config.js file