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>

extensions/vtk/src/utils/getReactVtkjsViewport.js

@@ -0,0 +1,5 @@
+export function getReactVtkjsViewport() {
+  return import(
+    /* webpackChunkName: "ReactVtkjsViewport" */ 'react-vtkjs-viewport'
+  );
+}