Feature/bulk upload status

- General
  - Makefile updated to run the job runner on `make run`
  - Use djrill to send email only on production mode. Use terminal logs instead
  - Don't minify javascript on development mode
- Bulk Upload
  - Add progress bars to follow the job progression :  
    A first one for the files reading, a second one for the objects creation
  - Timing the execution, tell at the end the time spent
  - Send an email to notify the end of the processing when
    - The job seems to be long (after 10s the files reading progression is under 20%)
    - The job in enqueued, not started yet