Add Prettier

[greglobinski]

All settings, except for singleQuote, are defaults Prettier values.

{
    "printWidth": 80,
    "singleQuote": true,
    "semi": true,
    "trailingComma": "es5",
    "bracketSpacing": true,
    "jsxBracketSameLine": false,
    "arrowParens": "avoid"
}

The properties

{
    "tabWidth": 4,
    "useTabs": false,
}

are not set because Prettier pulls them out from .editorconfig

indent_style = space
indent_size = 4

[piecioshka]

Awesome @greglobinski 👏