refactor: Reduce bundle size (#1575)

* async load cornerstoneWADOImageLoader chunk

* Lazy initializing of CornerstoneWADIImageLoader - delayed till Viewer creation

* Async loading of react-vtkjs-viewport

* withCornerstone HOC to wrap routes requiring CornerstoneWADOImageLoader initiazation

* removed dead code in comments

* initWeWorkers is no more. Remove al its references.

Co-authored-by: kedar.netelixir <kedar.choudhary@netelixir.com>
Co-authored-by: Danny Brown <danny.ri.brown@gmail.com>

platform/core/src/classes/StudyLoadingListener.js

@@ -1,10 +1,10 @@
 import cornerstone from 'cornerstone-core';
-import cornerstoneWADOImageLoader from 'cornerstone-wado-image-loader';
 import {
   clearStudyLoadingProgress,
   setStudyLoadingProgress,
 } from '../redux/actions';
 import StackManager from '../utils/StackManager';
+import { getCornerstoneWADOImageLoader } from '../utils/cornerstoneWADOImageLoader';
 
 class BaseLoadingListener {
   constructor(stack, options = {}) {
@@ -103,7 +103,8 @@ class DICOMFileLoadingListener extends BaseLoadingListener {
     this._checkCachedData();
   }
 
-  _checkCachedData() {
+  async _checkCachedData() {
+    const cornerstoneWADOImageLoader = await getCornerstoneWADOImageLoader();
     const dataSet = cornerstoneWADOImageLoader.wadouri.dataSetCacheManager.get(
       this._dataSetUrl
     );