Revert "1021662 - adding a class which inherits requests.auth.AuthBase and sets up proxy and user basic authentication headers correctly instead of overwriting each other"

This reverts commit 05c753651a4734b3749c9562c38733d38607fd36.
Revert since it was accidentally pushed to master instead of a branch which will be PR reviewed.
This reverts commit d04571650f890439f0188e3c65b67e8b15afc8f1.