Improve user experience for queue processes

[anjesh]

• queues are responsive and fast in the followings import
  • activity CSV importer
  • transactions importer
  • results importer
  • activity XML importer
• "how to use/run queue" is documented in readme.md

NOTE

when you upload the CSV or XML for import, it goes to the background queue and the script reads from the queue-outputs and the result is shown. The responses are not smooth, there are few hiccups during import phase and also the queue is hard to debug when something goes wrong. We need to refactor the queue code and also document them.