Addresses part of #16, (#71)

Integrate gatsby-plugin-intl for internationalization
Replaces static text with `intl.formatMessage` call and Links with `gatsby-plugin-intl` equivalent
Note: `npm install` now requires `--force` to install the latest `gatsby-plugin-intl` as it doesn't explicitly support gatsby3.0

client/src/pages/index.tsx

@@ -1,11 +1,15 @@
 import * as React from "react"
 import Layout from '../components/layout';
-
 // markup
-export default function IndexPage() {
+const IndexPage = () => {
+  
   return (
-      <Layout>
-        <title>Justice40</title>
-      </Layout>
+    <Layout>
+      <main>
+        <h2>Subheader</h2>
+      </main>
+    </Layout>
   )
-}
+}
+
+export default IndexPage;