Typed Sass Styling (#69)

* Addresses issue #16 -
Add styles via sass and module imports
Adds typed scss imports via gatsby-plugin-sass.
Makes use of .d.scss file generated by gatsby-plugin-scss-typescript,
but avoids importing that directly while they work out issue in gatsby v3.

* adding vscode config for easier local debugging

client/src/pages/index.tsx

@@ -1,15 +1,11 @@
 import * as React from "react"
-import {GovBanner} from '@trussworks/react-uswds';
+import Layout from '../components/layout';
 
 // markup
-const IndexPage = () => {
+export default function IndexPage() {
   return (
-      <main>
-        <GovBanner />
+      <Layout>
         <title>Justice40</title>
-        <h1>Justice40</h1>
-      </main>
+      </Layout>
   )
-}
-
-export default IndexPage;
+}