Add Vue.js Storefront API client

[neilmispelaar]

Create a Vue.js single page application that consumes the Shopify Storefront API to display products and and allow users to populate a shopping cart and checkout.

A lot of inspiration was taken from @tsavecodes and pull request #83 from the project

I'm throwing this out there to start a conversation - I know there is still a bit of work for this, but wanted to get your initial feedback as I continue to cross things off the todo list.

Dev Notes

• Boilerplate Vue.js project upgraded to use Vue 3 and the composition api, and Vuex for state management
• Tried to use TypeScript which was fun
• Created a ShopifyClient.ts static class to manage the API calls and normalize the data
• Uses the JavaScript AirBnb code style for linting
• Still have a few things on the to do list which is documented in the readme