Add simple route-based code splitting

src/components/PageLoader.tsx

@@ -0,0 +1,16 @@
+import React, { FC } from 'react'
+import { LoadingComponentProps as Props } from 'react-loadable'
+
+export const PageLoader: FC<Props> = ({ isLoading, pastDelay, error, retry, timedOut }) => {
+  const retryButton = <button onClick={retry}>retry</button>
+
+  if (error) {
+    return <div>Something went awry... do you wish to {retryButton}?</div>
+  } else if (timedOut) {
+    return <div>Taking some time... {retryButton}?</div>
+  } else if (pastDelay) {
+    return <div>Loading...</div>
+  } else {
+    return null
+  }
+}