feat(App): Loads mode extensions on demand (#3312)

* feat: Dynamic plugin imports

* Remove unused file

* Fix basic dev mode

* Fix the modes issue that Joe requested

* Merge fixes

* Add the ability to publish directory contents

* PR review changes

---------

platform/viewer/public/config/multiple.js

@@ -12,7 +12,7 @@ window.config = {
     },
   ],
   extensions: [],
-  modes: ['@ohif/mode-test'],
+  modes: ['@ohif/mode-test', '@ohif/mode-basic-dev-mode'],
   showStudyList: true,
   maxNumberOfWebWorkers: 4,
   // below flag is for performance reasons, but it might not work for all servers