* Requiring at least one args in a mutually exclusive group to be set
bulk_change_enrollment requires one of agrs: org or course to be set
for it to function correctly.
* Creating new function to verify initial password hash
Starting with django 2.1, the function is_password_usable no longer checks whether encode
is a valid password created by a django hasher(hasher in PASSWORD_HASHERS setting)
Adding this function to create constant behavior as we upgrade django versions
b45ac858ab