Relocate most of the code to MassUploadLibrary

Most of the code was genericised in the MassUploadLibrary repo.
Delete files, what is left is moved to Champlitte.py which handles
both metadata classes (Record and Collection).
Finish revamping Champlitte.py after code move
Add postprocessing capabilities to Task

- Add postprocessing for Joconde DIMS
- Minor import fixes following code restructuration