contrib: long-term overhaul

[S. Andrew Sheppard]

• Move the thumbnail generator in files.views / files.util to a separate PyPI package
• Make dbio a separate PyPI package (eventually) supporting arbitrary models; fully independent of vera (and possibly independent of wq.db, like django-rest-pandas is)
  • Edit: dbio relies on the identify pattern so it will still need to depend on wq.db.
• Move vera code to the existing PyPI package
• Probably leave chart, search and the rest of files as the remaining contrib apps.
  • Edit: Chart is dependent on vera though... fix this

[S. Andrew Sheppard]

See https://github.com/wq/django-media-thumbnailer

[S. Andrew Sheppard]

See https://github.com/wq/vera and https://github.com/wq/dbio.