New pyhton sample application: an upload sync controller

This is to be considered as a sample application that demonstrates upload synchronization capabilities such as:
- create containers on DMSs
- upload files to DMSs
- delete containers/files from DMSs
- update file metadata on DMSs (file renaming)

The controller tracks changes from a local folder and performs required operations on remote DMSs to reflect those changes (create/upload/delete).

The controller works one way only (local --> DMS) and do do reflect server side changes. The existing download sync controller sample app demonstrates this behavior.

The current code triggers the synchronization upon user manual action only. There is no folder monitoring to reflect changes automatically. I will add this functionality in a subsequent PR, once this PR is accepted.
Also, the metadata update (file renaming) will be implemented at this time.