Fix json encoder issues and nested queries (#94)

* Updated deprecated methods

* Get all respondent ids on a specific data

* Update routes and tests

Created a new route for get respondent id feature and updated tests for the same

* Optimize data storage and retrieval

Updated schema to store data in a more efficient way as per mongodb . Improved data retrieval for faster retrieval

* Replace hardcoded role strings with Role Manager class

* Fix json encoder issues and nested queries

* Fix json encoder issues and nested queries

* Fix json encoder issues and nested queries

* Fix json encoder issues and nested queries