Adding staff create load test

* Creates staff records by randomly picking them from a CSV file, which is generated by modules/tests/load/scripts/create_staff_data.py file.
* The helper being used are config.xml (which has the load information - subject to changes) and login.xml.

The helpers are located in modules/tests/load/helpers and the scripts to generate the data needed by the tests are present in modules/tests/load/scripts