Allow direct communication to Openshift through all user-related endpoints

Dependant on #177, as the next step to merge `CCI-MOC/openshift-acct-mgt`, we want all functions in the `OpenShiftResourceAllocator` class that make use of the `user.openshift.io` API  to have direct communication with the Openshift cluster. This includes the following functions:
- `create_federated_user`
- `assign_role_on_user`
- `remove_role_from_user`