chore: Switch asyncComponent to React Lazy/Suspense (Closes #1577) (#1582)

* Attempted Lazy load for OHIFCornerStoneViewport

* Converted dicom-(html, microscopy, pdf) & cornerstone extensions to React Lazy components

* Fixed incorrect import from OHIFDicomPDFSopClassHandler to ConnectedOHIFDicomPDFViewer

Co-authored-by: Ankit Mohan <ankit.mohan@live.in>
Co-authored-by: Erik Ziegler <erik.sweed@gmail.com>

extensions/dicom-pdf/src/index.js

@@ -1,11 +1,17 @@
-import asyncComponent from './asyncComponent.js';
+import React from 'react';
 import OHIFDicomPDFSopClassHandler from './OHIFDicomPDFSopClassHandler.js';
 
-const ConnectedOHIFDicomPDFViewer = asyncComponent(() =>
-  import(
-    /* webpackChunkName: "ConnectedOHIFDicomPDFViewer" */ './ConnectedOHIFDicomPDFViewer'
-  )
-);
+const Component = React.lazy(() => {
+  return import('./ConnectedOHIFDicomPDFViewer');
+});
+
+const ConnectedOHIFDicomPDFViewer = props => {
+  return (
+    <React.Suspense fallback={<div>Loading...</div>}>
+      <Component {...props} />
+    </React.Suspense>
+  );
+};
 
 export default {
   /**