Create instructions on how to setup the storefront graphql query

[vadym-space48]

hey @pfcodes

you can review how it's working in the widget-builder/src/services/fixtures

or here

https://github.com/bigcommerce/widget-builder/pull/23/files

[christensenep]

Hey @pfcodes, we agree this could be much better documented, we will be looking into improving this.