Update React documentation

[andrea-dintino]

npm i zenroom is not enough in React if Webpack is used then here is how to setup Zenroom (from @puria ):

...you need to configure webpack to exclude the wasm polyfills to work with react, we have done that previously for react as such: 

https://github.com/interfacerproject/interfacer-gui/blob/main/next.config.js#L24-L30

By disabling the modules that I sent you in the previous link!

OR

if you just want to client you can just import in the component in the template (vanilla html)

I just created now a small index.html to show the usage here:

https://github.com/puria/zenroom-web/blob/main/index.html