Adding a setting for cornerstone default image renderer

Packages/ohif-cornerstone/client/renderer.js

@@ -0,0 +1,4 @@
+import { Meteor, OHIF } from '../namespace';
+
+const rendererPath = 'settings.public.ui.cornerstoneRenderer';
+OHIF.cornerstone.renderer = OHIF.utils.ObjectPath.get(Meteor, rendererPath) || '';