Chore - update basic setup guide to mention an index.js file

[jasonbahl]

👋🏻 if I don't have a /src/pages/index.js file, things don't work well.

This could either be a hard-coded page or a faust page, such as:

import { getWordPressProps, WordPressTemplate } from "@faustwp/core"

export default function Page(props: any) {
  return <WordPressTemplate {...props} />
}

export function getStaticProps(ctx: any) {
  return getWordPressProps({ ctx })
}

(see: https://github.com/wp-graphql/wpgraphql.com/blob/master/src/pages/index.js)

but the [...wordPressNode] catch all doesn't seem to play nice with the / route.

For me, I still want to use WordPress + Faust on my home page, so I added an index.js file like the above. This should be called out in the docs.

[Fran-A-Dev]

@jasonbahl sounds good will add this chore!

[Fran-A-Dev]

Here is the PR @jasonbahl

I will get it reviewed and merged
#295