Removes a user from the Postgres server.

    CLI Example:

    .. code-block:: bash

        salt '*' postgres.user_remove 'username'

def user_remove(username,
                user=None,
                host=None,
                port=None,
                maintenance_db=None,
                password=None,
                runas=None):
    '''
    Removes a user from the Postgres server.

    CLI Example:

    .. code-block:: bash

        salt '*' postgres.user_remove 'username'
    '''
    return _role_remove(username,
                        user=user,
                        host=host,
                        port=port,
                        maintenance_db=maintenance_db,
                        password=password,
                        runas=runas)