Replace eslint style rules with prettier

[alexreardon]

Right now we have a lot of eslint rules including extending the airbnb rules.

I am keen to move all of the style rules to prettier (eg our custom eslint rule for dangling comma's)

However, I am keen to keep the eslint rules that are non-style related. Things like eslint-plugin-jsx-a11y and so on.

Here is my proposed .prettierrc config

{
  "trailingComma": "all",
  "semi": true,
  "tabWidth": 2,
  "useTabs": false,
  "singleQuote": true
}

[alexreardon]

This work should be done after #493, and probably at the same time as #525

[alexreardon]

Shipped in #581