Make Aspera Connector working on Nuxeo 11.X

The main purpose of this ticket is to make the Aspera addon installable an runnable on Nuxeo 11.X without errors and to be able to interact with Aspera to upload / download content using browse files / folders or Drag and Drop.

It takes into account the key points to be able to answer for SUPINT-1779 and to prepare the base things to be merged into master after the creation of the maintenance branch.