Align Aspera on Release 2021

Since the Platform 2021 LTS Release, we should align Aspera on this new Release and create the needed branches, tags, etc.
Note that we have also to align on WEB-UI 2021 Release that should be 3.X.X, still work in progress but guidelines already available here.

Despite being focused on LTS, while creating the needed artifacts we should have in mind the two future tracks: LTS and Cloud