[Conformance] Eslint package about hydrogen-v1

[graygilmore]

Should we use Typescript?

I'd like to see everything inside of our NPM packages use TypeScript (which I think most if not all of it is already?) but I'm hesitant to ship TypeScript for our starter template. In the future I'd love if we had both a JS and TS starter template but if we're only going to have one it should probably stick to JS.

[cartogram]

Other rules I think we should enable:

• @shopify/jsx-no-hardcoded-content
• @shopify/jsx-no-complex-expressions
• no-use-before-define
• no-unused-vars
• no-lone-blocks
• id-length

[jplhomer]

I think this is pretty well covered, but feel free to re-open with an updated scope.