`src/bin` code cleaning

[erikyao]

Modules Involved

In use; don't touch:

• hub.py

Are they obsolete? Delete or revise:

• build.py: wrong paths of imports
• dispatcher.py: imports DocDispatcher which is not available now
• dump.py: imports SourceManager which receives an asyncio loop to init. Current SourceManager don't have such a constructor
• upload.py: same problem with dump.py